Molybdenum alloy forge piece and preparation method thereof
By optimizing forging parameters through hydrogen-segmented gradient sintering, billet forging, repeated upsetting and annealing processes, the problems of uneven deformation and microstructure in large-size molybdenum alloy forgings were solved, resulting in high-performance molybdenum alloy forgings suitable for aerospace, nuclear industry and medical fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI COPPER TECHNOLOGY RESEARCH INSTITUTE CO LTD
- Filing Date
- 2026-02-24
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies struggle to produce large-sized molybdenum alloy forgings due to issues such as uneven deformation, uneven microstructure, low density, and poor mechanical properties. This results in short product lifespans, making it difficult to meet the stringent requirements of high-end equipment.
The process employs hydrogen-segmented gradient sintering, billet forging, repeated upsetting and drawing forging, and annealing. Combined with monitoring of forging process parameters, the uniformity and density of the forging structure are ensured. Through multiple deformation and annealing treatments, the forging process parameters are optimized to achieve uniform and dense large-size molybdenum alloy forgings.
A molybdenum alloy forging with uniform microstructure and good density was successfully prepared, which has good mechanical properties and meets the industrial production needs of large-size products. This solves the problems of uneven microstructure and poor mechanical properties in traditional forging methods.
Smart Images
Figure CN122033248A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rare and refractory metals technology, and in particular to a molybdenum alloy forging and its preparation method. Background Technology
[0002] Molybdenum and molybdenum alloys possess advantages such as high melting point, excellent high-temperature mechanical properties, and good thermal shock resistance, making them widely used in aerospace, nuclear industry, and medical fields. With technological advancements, high-end equipment requires larger-sized molybdenum alloy forgings. However, due to limitations in equipment and technological accumulation, common processing methods often employ unidirectional cumulative deformation to achieve the required dimensions. This can lead to insufficient deformation and uneven deformation, resulting in low density, poor mechanical properties, and uneven microstructure in the forgings. This directly impacts the service life of the finished product and makes it difficult to meet the stringent requirements of high-end equipment.
[0003] For large-size molybdenum alloy forgings, there are three main challenges in the manufacturing process: 1) During the sintering process, it is difficult to achieve uniform densification in different parts of the large-size blank, and controlling the heating rate and temperature is a challenge; 2) The degree of deformation varies in different parts of the forging of large-size forgings, and how to improve the uniformity of deformation by optimizing the processing method; 3) During the forging process, the surface of large-size forgings loses temperature rapidly, while the middle part hardly changes temperature. Different deformation temperatures can lead to uneven distribution of processing stress and deformation, and even cracking of the forgings. How to control the deformation process by monitoring the surface temperature is a challenge.
[0004] Based on this, we will continue to develop a manufacturing process suitable for large-size molybdenum alloy forgings to achieve densification and microstructure uniformity at different locations of the components. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a molybdenum alloy forging and its preparation method. The preparation method provided by this invention can obtain large-sized, uniformly structured, and high-performance molybdenum alloy forgings.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing a molybdenum alloy forging, comprising the following steps: S1. Mix molybdenum powder and doped powder evenly, and after cold isostatic pressing, use hydrogen to perform segmented gradient sintering to obtain sintered blanks. S2. The sintered billet is forged in a hydrogen atmosphere to achieve a total deformation of 36-65% to obtain an intermediate forging billet. S3. The intermediate forging billet is repeatedly upset and drawn under a hydrogen atmosphere to obtain a repeatedly upset and drawn forging billet; S4. The repeatedly upsetting and drawing forging billet is forged into a finished forging billet, and then annealed to obtain the molybdenum alloy forging.
[0007] The method for preparing molybdenum alloy forgings provided by this invention is applicable to the production of large-scale molybdenum alloy forgings. It mainly achieves the uniformity and density of the microstructure of large-scale molybdenum alloy forgings and good mechanical properties by optimizing the forging process and monitoring the forging process parameters.
[0008] This invention achieves preliminary control over the densification of the forging billet microstructure through segmented gradient hydrogen sintering. The sintered billet is then subjected to initial forging, and by controlling the total deformation range, sufficient deformation of the forging is ensured, resulting in an intermediate forging billet. Insufficient deformation leads to core cracking and uneven microstructure, while excessive deformation after initial forging and reflow forging results in excessive local stress and forging cracking. Subsequently, repeated upsetting and drawing forging of the intermediate forging billet ensures uniform deformation during processing, solving the problems of microstructure uniformity and anisotropy in large-size molybdenum alloy forgings. Finally, through finished product forging and annealing, molybdenum alloy forgings with a dense and uniform microstructure and a diameter of 100-300 mm can be successfully prepared.
[0009] The preparation method provided by this invention adopts a forging process of hydrogen segmented gradient sintering, pre-forging, repeated upsetting and drawing, finished product forging and annealing. Combined with parameter monitoring during the forging process, it successfully produces large-size molybdenum alloy forgings with a uniform and dense structure and good mechanical properties (φ=100-300mm). This method can meet the industrial production needs of large-size products, ensure the stability of the product structure and batch consistency, and adapt to the industrial production needs of large-size molybdenum alloy forgings. It solves the problems of uneven structure and poor mechanical properties and stability of large-size forgings prepared by traditional forging methods.
[0010] Preferably, in S1, the doped powder includes at least one of rare earth oxides, refractory metal oxides, and pure metals, such as lanthanum oxide, zirconium oxide, etc.
[0011] Preferably, in step S1, the specific conditions for mixing the molybdenum powder and the dopant powder are as follows: before mixing, the equipment is purged with argon gas, and after the argon gas purging is completed, mixing begins, with a mixing time of 4-8 hours.
[0012] Preferably, in step S1, the maximum static pressure of the cold isostatic pressing is 175-250 MPa, and the holding time is 5-15 min.
[0013] Preferably, in step S1, the hydrogen segmented gradient sintering specifically involves: First, raise the temperature to 800-1200℃ at a rate of 100-200℃ / h, and hold at different heating points for 2-4 hours respectively; Then, the temperature is increased to 1400-2000℃ at a rate of 50-100℃ / h, and held at different heating points for 2-4 hours respectively. Finally, raise the temperature to 2100-2250℃ at a rate of 45-55℃ / h and hold for 8-12 hours.
[0014] The sintering stage combines low-temperature pre-sintering and high-temperature densification gradient sintering to remove impurities in stages and control the densification process during sintering, thereby achieving uniform purification and densification in large batches.
[0015] More preferably, in step S1, the hydrogen segmented gradient sintering specifically involves: First, raise the temperature to 1200℃ at a rate of 100-200℃ / h, and then hold the temperature for 2-4 hours at 800℃, 1000℃, and 1200℃ respectively. Then, the temperature is increased to 2000℃ at a rate of 50-100℃ / h, and held at 1400℃, 1800℃ and 2000℃ for 4 hours respectively. Finally, raise the temperature to 2100-2250℃ at a rate of 45-55℃ / h and hold for 8-12 hours.
[0016] Preferably, in S2, the conditions for billet forging are: heating at 1300-1500℃ for 1-4 hours, then performing axial upsetting or radial elongation forging on the sintered billet, with a final forging temperature ≥1000℃, and then re-forging in the same direction 1-3 times.
[0017] More preferably, in step S2, the reheating time for re-forging is 15-30 minutes, and the deformation is 20-30%.
[0018] Furthermore, by controlling the single-pass forging and the total deformation after forging, it can be ensured that the forging is deformed evenly and fully.
[0019] Preferably, in step S2, the aspect ratio of the sintered billet is ≥1.4. When the length-to-diameter ratio of the sintered billet is 1.4-2, the sintered billet is subjected to axial upsetting forging. When the length-to-diameter ratio of the sintered billet is greater than 2, the sintered billet is subjected to radial elongation forging.
[0020] Controlling the length-to-diameter ratio of the initial forging and reflow forging, combined with monitoring the final forging temperature, ensures successful initial forging deformation: Control the length-to-diameter ratio of the sintered billet to above 1.4, and then perform initial forging in different directions according to different length-to-diameter ratio ranges: When the length-to-diameter ratio of the sintered billet is 1.4-2, perform axial upsetting initial forging, controlling the deformation amount so that the length-to-diameter ratio of the intermediate forging billet is about 0.8 or above; when the length-to-diameter ratio of the sintered billet is >2, perform radial drawing initial forging, controlling the deformation amount so that the length-to-diameter ratio of the intermediate forging billet is about 2.7 or above.
[0021] Preferably, if the forging is axial upsetting forging, no slitting is performed; if the forging is radial drawing forging, the intermediate forging blank is slitting.
[0022] Preferably, in step S3, the conditions for repeated upsetting and drawing forging are as follows: heating at 1200-1400℃ for 0.5-1h, followed by axial upsetting or radial drawing forging in the first heat, and radial drawing or axial upsetting forging in the second heat along different directions of the first heat, with a deformation of 20-30%, a final forging temperature ≥950℃, and repeated upsetting and drawing forging 1-3 times.
[0023] Preferably, in step S3, the length-to-diameter ratio of the intermediate forging billet is 0.8-2. When the length-to-diameter ratio of the intermediate forging billet is 0.8-1.2, the first heat of repeated upsetting and drawing forging is used for elongation forging; When the length-to-diameter ratio of the intermediate forging billet is 1.2-2, the first heat of repeated upsetting and drawing forging is used for upsetting.
[0024] Intermediate forging blanks obtained from radial drawing and forging can be slit using methods including sawing machines, wire cutting machines, and water jet cutting to control their length-to-diameter ratio and adapt to different repeated upsetting and drawing forging requirements.
[0025] Preferably, in step S4, the forging conditions for the finished product are: heating at 1200-1400℃ for 15-30 minutes, followed by axial upsetting or radial drawing forging, with a deformation of 20-30%, a final forging temperature ≥950℃, and re-forging in the same direction 1-3 times.
[0026] Preferably, in step S4, the reflow time during multiple forging processes is 15-30 minutes, the deformation amount is 20-30%, and the final forging temperature is ≥950℃.
[0027] Preferably, in step S4, the annealing is carried out in a hydrogen atmosphere at a temperature of 900-1300°C for 0.5-2 hours.
[0028] By optimizing repeated upsetting and drawing processes and monitoring the final forging temperature, uniform deformation during the processing can be ensured, thus solving the problems of microstructure uniformity and anisotropy in large-size molybdenum alloy forgings.
[0029] Preferably, the upsetting forging and drawing forging are carried out using upsetting dies and drawing dies, respectively, and the dies are preheated to 100-200°C before use.
[0030] Preferably, the preparation method further includes a machining process for the molybdenum alloy forging.
[0031] Secondly, the present invention provides a molybdenum alloy forging prepared by the above-mentioned method for preparing molybdenum alloy forgings.
[0032] Thirdly, the present invention provides applications of the above-mentioned molybdenum alloy forgings in the aerospace, nuclear industry, or medical fields.
[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for preparing molybdenum alloy forgings, which can improve the uniformity of the microstructure of large-size molybdenum alloy forgings and effectively overcome the shortcomings of existing technologies. It can produce large-size molybdenum alloy forgings with uniform microstructure and controllable anisotropy. The preparation method has simple production process, high yield, and is conducive to industrial production. It can produce large-size molybdenum alloy forgings with diameters of 100-300mm and excellent performance, and has high practical value. Attached Figure Description
[0034] Figure 1 This is a schematic diagram of the process flow for preparing the molybdenum alloy forgings of the present invention in Example 1; Figure 2 The image shows the appearance of the molybdenum alloy forging obtained by the method for preparing molybdenum alloy forgings of the present invention in Example 1. Figure 3 This is a microstructure diagram of the molybdenum alloy forging obtained by the preparation method of the molybdenum alloy forging of the present invention in Example 1. Detailed Implementation
[0035] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available reagents and materials.
[0036] Example 1 An embodiment of the molybdenum alloy forging and its preparation method according to the present invention is described below. The specific process flow is as follows. Figure 1 : S1. Add molybdenum powder and lanthanum oxide powder to a ball mill at a mass ratio of 99:1, rotate at 200 rpm / min, and mill for 8 hours. Dry the resulting mixed powder and then put it into a mold for cold isostatic pressing. Set the maximum pressure to 200 MPa and the holding time to 15 min to obtain the pressed blank. The compact was sintered by first heating it to 800℃, 1000℃ and 1200℃ at a rate of 100℃ / h, and holding it at each temperature node for 2h. Then, it was heated to 1400℃, 1800℃ and 2000℃ at a rate of 100℃ / h, and held at each temperature node for 4h. Finally, it was heated to 2150℃ at a rate of 50℃ / h and held for 12h to obtain a molybdenum alloy sintered compact with a diameter of 150mm, a length of 500mm and an aspect ratio of 3.33. S2. Heat the molybdenum alloy sintered billet to 1400℃ and hold for 2 hours. Then, perform radial elongation forging, controlling the deformation at 20-25%. Reheat in the furnace at 1300-1400℃ for 20 minutes, and perform two heats of forging in the same direction, controlling the deformation at 20-25%. The final forging temperature is controlled above 1000℃ to obtain an intermediate forging billet with a diameter of approximately 105mm and a length of approximately 1000mm, with a total deformation of 51%. S3. Cut the intermediate forging billet into 6 pieces, each with a diameter of 105mm, a length of 165mm, and an aspect ratio of 1.57. Hold the cut intermediate forging billet at 1300℃ for 1 hour for the first upsetting rough forging, with the deformation controlled at 30%. Then, return it to the furnace and hold it for 20 minutes for the second drawing forging, with the deformation controlled at 30%. The final forging temperature is controlled above 950℃. Repeat the upsetting and drawing process twice to obtain a repeatedly upsetting and drawing forging billet with a diameter of approximately 105mm and a length of approximately 165mm, with an aspect ratio of 1.57. S4. The repeatedly upset forged billet is reheated at 1300℃ for 20 minutes and then subjected to three-stage upsetting forging, with the deformation controlled at 30% and the final forging temperature controlled above 950℃, to obtain a finished forging with a diameter of approximately 185mm and a height of approximately 55mm; then it is annealed at 1000℃ for 2 hours, and finally machined to obtain a large-size molybdenum alloy forging with a diameter of 180mm and a height of 50mm, with an appearance as shown. Figure 2 As shown.
[0037] Example 2 An embodiment of the molybdenum alloy forging and its preparation method according to the present invention is as follows: S1. Add molybdenum powder and lanthanum oxide powder to a ball mill at a mass ratio of 99:1, rotate at 200 rpm / min, and mill for 8 hours. Dry the resulting mixed powder and then put it into a mold for cold isostatic pressing. Set the maximum pressure to 200 MPa and the holding time to 15 min to obtain the pressed blank. The compact was sintered by first heating it to 800℃, 1000℃ and 1200℃ at a rate of 100℃ / h, and holding it at each temperature node for 2h. Then, it was heated to 1400℃, 1800℃ and 2000℃ at a rate of 100℃ / h, and held at each temperature node for 4h. Finally, it was heated to 2150℃ at a rate of 50℃ / h and held for 12h to obtain a molybdenum alloy sintered compact with a diameter of 200mm, a length of 350mm and an aspect ratio of 1.75. S2. Heat the molybdenum alloy sintered billet to 1500℃ and hold for 1.5 hours. Then perform axial upsetting forging, controlling the deformation at 20-25%. Return the billet to the furnace at 1400-1500℃ and hold for 20 minutes. Perform one heat of forging in the same direction, controlling the deformation at 20-25%. The final forging temperature is controlled above 1000℃ to obtain an intermediate forging billet with a diameter of approximately 255mm and a length of approximately 225mm, an aspect ratio of 1, and a total deformation of 36%. S3. The intermediate forging billet is held at 1400℃ for 1 hour for the first heat drawing forging, with the deformation controlled at 25%. Then it is put back into the furnace and held for 30 minutes for the second heat upsetting forging, with the deformation controlled at 25%. The final forging temperature is controlled above 950℃. The upsetting and drawing process is repeated 3 times to obtain a repeatedly upsetting forging billet with a diameter of about 255mm and a length of about 225mm, with a length-to-diameter ratio of 1. S4. The repeatedly upsetting and drawing forged billet is reheated at 1400℃ for 30 minutes and then subjected to two-stage upsetting forging. The deformation is controlled at 25%, and the final forging temperature is controlled above 950℃ to obtain a finished forging with a diameter of about 320mm and a height of about 125mm. Then, it is annealed at 1100℃ for 2 hours and finally machined to obtain a large-size molybdenum alloy forging with a diameter of 300mm and a height of 120mm.
[0038] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the sintering conditions for the pressed blank in step S1 are changed as follows: First, raise the temperature to 1200℃ at a rate of 100℃ / h and hold for 2 hours. Then, raise the temperature to 2000℃ at a rate of 100℃ / h and hold for 2 hours. Finally, raise the temperature to 2150℃ at a rate of 50℃ / h and hold for 12 hours.
[0039] Comparative Example 2 The preparation method of the molybdenum alloy forging in Comparative Example 2 is as follows: S1. Refer to Example 1; S2. A sintered molybdenum alloy billet with a diameter of 150 mm and a length of 500 mm is heated to 1400℃ and held for 2 hours. Then, it is radially drawn into an open forging, with the deformation controlled at 10-20%. It is then reheated in the furnace at 1300-1400℃ and held for 20 minutes. Two forgings are performed in the same direction, with the deformation controlled at 10-20%. The final forging temperature is controlled above 1000℃ to obtain an intermediate forging billet with a diameter of approximately 125 mm and a length of approximately 690 mm. The total deformation is approximately 30%. S3. Cut the intermediate forging billet into 5 pieces, each with a diameter of 125mm, a length of 120mm, and an aspect ratio of 0.96. Hold the cut intermediate forging billet at 1300℃ for 1 hour for the first heat drawing forging, with the deformation controlled at 20-30%. Then, return it to the furnace and hold it for 20 minutes for the second heat upsetting forging, with the deformation controlled at 20-30%. The final forging temperature is controlled above 950℃. Repeat the upsetting and drawing process twice to obtain a repeatedly upsetting forging billet with a diameter of approximately 125mm and a length of approximately 120mm, with an aspect ratio of 0.96. S4. Referring to the conditions of Example 1, the repeatedly upset forged billet is subjected to multiple upsetting forgings to obtain a finished forging with a diameter of about 185 mm and a height of about 55 mm; then it is annealed at 1000°C for 2 hours, and finally machined to obtain a large-size molybdenum alloy forging with a diameter of 180 mm and a height of 50 mm.
[0040] Comparative Example 3 The only difference between Comparative Example 4 and Example 1 is that after the S3 cutting, the repeated upsetting and drawing forging steps are not performed. Instead, the S4 step is performed directly to forge the forging blank with a diameter of about 105 mm and a length of about 165 mm, perform finished product forging, annealing and machining to obtain a large-size molybdenum alloy forging.
[0041] Comparative Example 4 The only difference between Comparative Example 4 and Example 2 is that after forging in S2, the repeated upsetting and drawing forging steps are not performed. Instead, step S4 is performed directly to forge, anneal, and machine the intermediate forging billet with a diameter of about 255 mm and a length of about 225 mm to obtain a large-size molybdenum alloy forging.
[0042] Example of effect To investigate the properties of the molybdenum alloy forgings prepared by the method provided in this invention, the molybdenum alloy forgings in the examples and comparative examples were subjected to the following tests: (1) Structure uniformity: Samples were taken from different locations such as the core and the edge to observe the structure uniformity of the forging under an optical microscope; (2) Processing defects: Refer to JJG 746-2004 and JB / T 10061-1999 A to test whether the forgings have defects such as cracking; (3) Mechanical properties: Refer to GB / T 3876-2017 to test the room temperature tensile strength and elongation after fracture (longitudinal).
[0043] The results are shown in Table 1 below. Figure 3 ,in Figure 3 This is a microstructure diagram of the molybdenum alloy forging in Example 1 as observed under an optical microscope.
[0044] Table 1 Combining Table 1 and Figure 3 As can be seen, the molybdenum alloy forgings prepared by the method of the present invention can realize the preparation of large-sized molybdenum-lanthanum alloy forgings with uniform and dense structure, without processing defects, and with good mechanical properties, longitudinal room temperature tensile strength ≥600MPa, and elongation after fracture ≥20%.
[0045] In contrast, Comparative Example 1 did not undergo segmented gradient sintering, resulting in the inability to effectively remove impurities from the molybdenum alloy sintered billet. Furthermore, the uneven distribution of microstructure and density led to reduced purity and poor microstructure uniformity in the final molybdenum alloy forging, with numerous core cracks and defects, resulting in significantly reduced mechanical properties. Comparative Example 2 suffered from insufficient total deformation during the initial forging, leading to inadequate forging of the billet, failure to deform the core, and subsequent core cracking defects during deformation. Comparative Examples 3 and 4 lacked repeated upsetting and drawing forging, resulting in uneven microstructure at the edges and core of the forgings, and their mechanical properties failed to meet requirements.
[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a molybdenum alloy forging, characterized in that, Includes the following steps: S1. Mix molybdenum powder and doped powder evenly, and after cold isostatic pressing, use hydrogen to perform segmented gradient sintering to obtain sintered blanks. S2. The sintered billet is forged in a hydrogen atmosphere to achieve a total deformation of 36-65% to obtain an intermediate forging billet. S3. The intermediate forging billet is repeatedly upset and drawn under a hydrogen atmosphere to obtain a repeatedly upset and drawn forging billet; S4. The repeatedly upsetting and drawing forging billet is forged into a finished forging billet, and then annealed to obtain the molybdenum alloy forging.
2. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S1, the maximum static pressure of the cold isostatic pressing is 175-250 MPa, and the holding time is 5-15 min.
3. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S1, the hydrogen segmented gradient sintering specifically involves: First, raise the temperature to 800-1200℃ at a rate of 100-200℃ / h, and hold at different heating points for 2-4 hours respectively; Then, the temperature is increased to 1400-2000℃ at a rate of 50-100℃ / h, and held at different heating points for 2-4 hours respectively. Finally, raise the temperature to 2100-2250℃ at a rate of 45-55℃ / h and hold for 8-12 hours.
4. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S2, the conditions for billet forging are: heating at 1300-1500℃ for 1-4 hours, then performing axial upsetting or radial elongation forging on the sintered billet, with a final forging temperature ≥1000℃, and then re-forging in the same direction 1-3 times.
5. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S2, the aspect ratio of the sintered billet is ≥1.4: When the length-to-diameter ratio of the sintered billet is 1.4-2, the sintered billet is subjected to axial upsetting forging. When the length-to-diameter ratio of the sintered billet is greater than 2, the sintered billet is subjected to radial elongation forging.
6. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S3, the conditions for repeated upsetting and drawing forging are as follows: heating at 1200-1400℃ for 0.5-1h, followed by axial upsetting or radial drawing forging in the first heat, and radial drawing or axial upsetting forging in the second heat along different directions of the first heat, with a deformation of 20-30%, a final forging temperature ≥950℃, and repeated upsetting and drawing forging 1-3 times.
7. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S3, the length-to-diameter ratio of the intermediate forging billet is 0.8-2. When the length-to-diameter ratio of the intermediate forging billet is 0.8-1.2, the first heat of repeated upsetting and drawing forging is used for elongation forging; When the length-to-diameter ratio of the intermediate forging billet is 1.2-2, the first heat of repeated upsetting and drawing forging is used for upsetting.
8. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In S4, the forging conditions of the finished product are as follows: heating at 1200-1400℃ for 15-30 minutes, followed by axial upsetting or radial drawing forging, with a deformation of 20-30%, a final forging temperature ≥950℃, and re-forging in the same direction 1-3 times.
9. The method for preparing the molybdenum alloy forging as described in claim 1, characterized in that, In step S4, annealing is carried out in a hydrogen atmosphere at a temperature of 900-1300℃ for a time of 0.5-2 hours.
10. A molybdenum alloy forging prepared by the method for preparing molybdenum alloy forgings according to any one of claims 1-9.