Processing method of high-strength niobium alloy

Abstract

The invention provides a high-strength niobium alloy processing method, which relates to the technical field of alloy processing, and comprises the following steps: step 1, ingot casting preparation: niobium, tungsten, tantalum, molybdenum, zirconium and carbon are subjected to powder mixing and ingot casting to obtain a first alloy product; step 2, extrusion processing: heating the first alloy product by adopting a medium-frequency induction furnace, and carrying out extrusion treatment by adopting an extrusion ingot supply device to obtain a second alloy product; step 3, forging: performing intermediate annealing treatment on the extruded second alloy product twice by adopting a first annealing process in the forging process to obtain a third alloy product; wherein free forging treatment is carried out on the alloy product between the two times of intermediate annealing treatment; and (4) finished product processing: carrying out finished product annealing treatment on the third alloy product by adopting a second annealing process to obtain the final high-strength niobium alloy. Wherein in the second annealing process, the temperature is increased to 1200-1450 DEG C at the speed of 18-20 DEG C / min, and heat preservation is conducted for 60-120 min. According to the scheme, the strength of the niobium alloy can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy processing, and in particular to a processing method of a high-strength niobium alloy. Background Art

[0002] With the rapid development of cutting-edge fields such as aerospace, nuclear energy industry, high-end medical equipment, and chemical equipment, the requirements for the comprehensive performance of materials are becoming increasingly stringent. As a high-performance structural material, niobium alloys are irreplaceable in high-temperature, highly corrosive, and extreme mechanical environments, and are widely used in cutting-edge industries. For example, the melting point of niobium alloys can reach as high as 2468°C, and they still maintain oxidation resistance at high temperatures of 1200°C, making them suitable for use in scenarios such as aerospace that require high stability in extreme environments. For another example, niobium alloys have low density, high thermal conductivity, and excellent resistance to radiation damage, and can be used in superconducting and energy equipment. For another example, niobium alloys have excellent biocompatibility and non-magnetic characteristics, and can be used in medical devices such as artificial bone joints and heart stents.

[0003] However, despite their many outstanding properties, niobium alloys have long been limited to a medium-strength tensile strength range of 200-400 MPa, and their elongation is also relatively low. For example, the existing Nb521 alloy has low tensile strength at both room and elevated temperatures. Furthermore, this insufficient room-temperature tensile strength often leads to deformation when increasing the preload on fasteners, leading to component failure. Therefore, there is an urgent need for a processing solution for high-strength niobium alloys. Summary of the Invention

[0004] In view of this, in order to address the above shortcomings, it is necessary to propose a processing method for high-strength niobium alloy to improve the strength of niobium alloy.

[0005] The present invention provides a method for processing a high-strength niobium alloy, comprising the following steps: Step 1, ingot preparation: using niobium, tungsten, tantalum, molybdenum, zirconium and carbon to mix powder and cast an ingot to obtain a first alloy product; Step 2, extrusion processing: heating the first alloy product using a medium frequency induction furnace and extruding it using an extrusion ingot feeder to obtain a second alloy product; Step 3, forging: In the forging process, the first annealing process is used to perform two intermediate annealing treatments on the extruded second alloy product to obtain a third alloy product; wherein, the alloy product is subjected to free forging between the two intermediate annealing treatments; Step 4, finished product processing: The third alloy product is subjected to finished product annealing treatment using a second annealing process to obtain a final high-strength niobium alloy; wherein the second annealing process is: heating to 1200-1450°C at 18-20°C / min and holding at that temperature for 60-120 minutes.

[0006] Preferably, the ingot preparation process in step 1 specifically includes: S11: Mixing, sintering and melting niobium, tungsten, tantalum, molybdenum, zirconium and carbon as raw materials; S12: Ingots are formed by vacuum electron beam melting and water-cooled crucible casting; S13: sawing the cast ingot according to preset specifications; S14: The sawn product is rounded to reduce the extrusion breakthrough pressure and prevent damage to the extrusion die; S15: A process of keeping the temperature at 1350℃~1450℃ for 60~120min is used to perform homogenization heat treatment on the product after the arc chamfer to obtain the first alloy product, so as to eliminate the casting stress and improve the plasticity and strength of the material by precipitating secondary relative materials.

[0007] Preferably, in step S11, the mass percentage of tantalum is (6~7)%, the mass percentage of tungsten is (6~7)%, the mass percentage of molybdenum is (1.7~2.3)%, the mass percentage of zirconium is (0.9~1.2)%, the mass percentage of carbon is (0.05~0.12)%, and the remainder is niobium.

[0008] Preferably, the extrusion process of step S2 specifically includes: S21: uniformly coating an anti-oxidation coating on the surface of the first alloy product; S22: Using a medium frequency induction furnace, a multi-temperature gradient heating process is used to extrusion heat the product after applying the anti-oxidation coating; S23: The extruded and heated product is transferred to an extrusion ingot feeder for extrusion to obtain a second alloy product.

[0009] Preferably, in step S22, the product coated with the anti-oxidation coating is extruded and heated using a multi-temperature gradient heating process, including: Insulation platforms at 800°C, 1000°C, 1100°C and 1200°C~1300°C are designed to heat the products coated with the antioxidant coating from low temperature to high temperature in sequence; the total heating time is 30~45 minutes, and the insulation time at 1200°C~1300°C is 2~10 minutes.

[0010] Preferably, the extrusion parameters in step S23 include: The conversion time is no more than 50 seconds, the extrusion speed is 40~120mm / s, the extrusion temperature is 1200~1350℃, and the extrusion breakthrough pressure is 25~34MN; the extrusion die and extrusion barrel need to be preheated to 350-650℃ in advance, and the extrusion die is filled and lubricated with glass pads, and the extrusion barrel is sprayed with a mixture of graphite, graphite emulsion, molybdenum disulfide and grease for lubrication.

[0011] Preferably, the forging process in step 3 specifically includes: S31: sawing and shrinking the second alloy product and then grinding it to remove defects on the extrusion surface; S32: Pickling the polished product to give the surface of the product a metallic luster; S33: performing a first intermediate annealing treatment on the product after pickling treatment by using the first annealing process to eliminate the internal stress of the product; S34: heating the product after the first intermediate annealing treatment to 1300-1700° C. using a medium frequency induction furnace, and drawing and forging the product to a first preset length; S35: heating the product after the drawing forging to 1050-1150° C. in a box furnace, and radially forging the product to a first preset diameter; S36: Pickling the radially forged product until the surface of the product presents a metallic luster; S37: performing a second intermediate annealing treatment on the product after the pickling treatment using the first annealing process to eliminate the internal stress of the product; S38: sawing the product after the second intermediate annealing treatment into a second preset length, and machining it to a second preset diameter; S39: The machined product is subjected to rotary forging to a target diameter to obtain a third alloy product.

[0012] Preferably, the first annealing process is: in a vacuum degree not greater than 3.0×10 -3 Pa, and then the temperature was raised to 1350±10°C within 70 minutes. After keeping the temperature for 90±5 minutes, the temperature was lowered to less than 80°C and the furnace was taken out. No argon gas was added during the cooling process.

[0013] Preferably, before the finished product processing in step 4, the third alloy product is pickled.

[0014] Preferably, the pickling solution for pickling treatment is prepared from hydrofluoric acid, hydrochloric acid and nitric acid in a mass ratio of 1.13:2.37:4.2; wherein, the pickling process of step S32 and step S36 is: soaking the product in the pickling solution, and rinsing with clean water every hour until the surface of the product presents a metallic luster; the pickling time for the third product is 10 minutes.

[0015] As can be seen from the above technical solution, the processing method for a high-strength niobium alloy provided in an embodiment of the present invention first prepares a mixed powder casting ingot using niobium, tungsten, tantalum, molybdenum, zirconium, and carbon. The first metal product obtained from the casting is then heated in a medium-frequency induction furnace and extruded using an extrusion ingot feeder. Furthermore, the extruded second alloy product undergoes two intermediate annealing treatments using a first annealing process, and the alloy product undergoes free forging between the two annealing treatments. Finally, the third alloy product undergoes a final annealing treatment using a second annealing process to obtain the final high-strength niobium alloy. Thus, by adding tantalum to the raw materials used to prepare the niobium alloy, the room temperature tensile strength and high temperature tensile strength can be improved, thereby reducing the occurrence of deformation and effective damage in fasteners when the preload is increased. Furthermore, by optimizing the annealing process and other processes during the processing of the niobium alloy, the strength of the niobium alloy can be improved by optimizing process parameters, thereby preventing cracking during the processing of highly alloyed alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of a method for processing a high-strength niobium alloy provided by an embodiment of the present invention.

[0017] Figure 2 This is the metallographic image of sample A1.

[0018] Figure 3 This is the metallographic image of sample B1.

[0019] Figure 4 This is the metallographic image of sample C1.

[0020] Figure 5 This is the metallographic image of sample D1.

[0021] Figure 6 This is the metallographic image of sample E1. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] like Figure 1 As shown, an embodiment of the present invention provides a method for processing a high-strength niobium alloy, comprising the following steps: Step 1, ingot preparation: using niobium, tungsten, tantalum, molybdenum, zirconium and carbon to mix powder and cast an ingot to obtain a first alloy product; Step 2, extrusion processing: heating the first alloy product using a medium frequency induction furnace and extruding it using an extrusion ingot feeder to obtain a second alloy product; Step 3, forging: In the forging process, the first annealing process is used to perform two intermediate annealing treatments on the extruded second alloy product to obtain a third alloy product; wherein, the alloy product is subjected to free forging between the two intermediate annealing treatments; Step 4, finished product processing: The third alloy product is subjected to finished product annealing treatment using a second annealing process to obtain a final high-strength niobium alloy; wherein the second annealing process is: heating to 1200-1450°C at 18-20°C / min and holding at that temperature for 60-120 minutes.

[0024] In this embodiment, by adding tantalum to the raw materials used to prepare the niobium alloy, the room temperature and high temperature tensile strengths can be increased, thereby reducing deformation and effective damage to fasteners when the preload is increased. Simultaneously, by optimizing the annealing process and other processes involved in processing the niobium alloy, the strength of the niobium alloy can be improved by optimizing process parameters, thereby avoiding cracking during the processing of highly alloyed alloys. For example, the high-strength niobium alloy obtained based on this solution is a multicomponent niobium alloy. This alloy can be strengthened at both room temperature and high temperature by adding a certain amount of tantalum to a conventional medium-strength niobium alloy. Furthermore, to further enhance the alloy's room temperature and high temperature performance, the ratios of tungsten, molybdenum, zirconium, and carbon can be increased to a certain extent. The resulting niobium alloy product exhibits higher room temperature and high temperature tensile strength than conventional medium-strength niobium alloys, such as Nb521, while also exhibiting certain machinability.

[0025] For step 1, the ingot preparation process can be specifically implemented through the following steps: S11: Mixing, sintering and melting niobium, tungsten, tantalum, molybdenum, zirconium and carbon as raw materials; This step aims to mix powders. Tantalum powder, tungsten powder, molybdenum powder, and niobium powder are considered for mixing. Carbon is added according to the oxygen content of the mixed powders for blending. Then, a press is used to press and form the powders before sintering. After sintering, the powders are welded, bundled, and assembled with zirconium plate semicircular electrodes, followed by multiple electron beam furnace smelting. Specifically, in this step, the mass percentages of tantalum are (6-7)%, tungsten (6-7)%, molybdenum (1.7-2.3)%, zirconium (0.9-1.2)%, carbon (0.05-0.12)%, and the remainder is niobium. Preferably, the composition is 6 tantalum, 6 tungsten, 2 molybdenum, 1 zirconium, and 0.08 carbon, i.e., 6% tantalum, 6% tungsten, 2% molybdenum, 1% zirconium, and 0.08% carbon, with the remainder being niobium.

[0026] S12, melting and casting: using vacuum electron beam melting and water-cooled crucible casting to form ingots; S13: sawing the cast ingot according to preset specifications; For example, in this step, sawing can be performed according to φ200~φ210×400~550mm.

[0027] S14: The sawn product is rounded to reduce the extrusion breakthrough pressure and prevent damage to the extrusion die; In this step, consider making one end of the extrusion a 45°×2~10mm or R20 arc chamfer to reduce the extrusion breakthrough pressure and prevent damage to the extrusion die.

[0028] S15: A process of keeping the temperature at 1350℃~1450℃ for 60~120min is used to perform homogenization heat treatment on the product after the arc chamfer to obtain the first alloy product, so as to eliminate the casting stress and improve the plasticity and strength of the material by improving the casting structure and precipitating secondary precipitation.

[0029] For step 2, consider the following steps to implement the extrusion process: S21: uniformly coating an anti-oxidation coating on the surface of the first alloy product; This step involves extrusion coating the surface of the first alloy product with a specialized anti-oxidation coating consisting of graphite emulsion, high-temperature glass powder, and glass adhesive. Specifically, a box-type resistance furnace can be used to preheat the surface to 80-120°C. A mixture of graphite emulsion, high-temperature glass powder, and an appropriate amount of glass adhesive or water glass is then sprayed on the surface and evenly applied by brush. The coating thickness is typically 0.3-0.6 mm.

[0030] S22: Using a medium frequency induction furnace, a multi-temperature gradient heating process is used to extrusion heat the product after applying the anti-oxidation coating; In this step, heating is performed using a medium-frequency induction furnace. Consider designing heat-holding platforms at 800°C, 1000°C, 1100°C, and 1200°C-1300°C. The anti-oxidation-coated product is heated sequentially from low to high temperatures. The total heating time is 30-45 minutes, and the holding time at 1200°C-1300°C is 2-10 minutes.

[0031] S23: The extruded and heated product is transferred to an extrusion ingot feeder for extrusion to obtain a second alloy product.

[0032] In this step, the ingot is sent from the heating furnace to the extrusion feeder for extrusion, and the time from the heating furnace to the extrusion feeder is ensured to be no more than 50 seconds. The extrusion die and the extrusion barrel of the extrusion feeder need to be preheated in advance, and the preheating temperature is 350-650°C. The extrusion die and the extrusion barrel need to be lubricated. The extrusion die is filled and lubricated with a glass pad (a lubricant formed by mixing high-temperature glass powder and glass glue), and the extrusion barrel is sprayed with a mixture of graphite, graphite emulsion, molybdenum disulfide and grease. The extrusion speed is 40~120mm / s, the extrusion temperature is 1200~1350°C, the extrusion breakthrough pressure is 25~34MN, the extrusion system adopts a φ220 system, and the size of the extruded product is φ118~φ128mm.

[0033] For step 3, the forging process can be specifically implemented through the following steps: S31: sawing and shrinking the second alloy product and then grinding it to remove defects on the extrusion surface; In this step, the extruded product is sawn to remove the tail. Then, it is polished with a bench grinder to remove surface defects such as cracks, grooves, and oxide scale.

[0034] S32: Pickling the polished product to give the surface of the product a metallic luster; In this step, consider soaking the polished product in an acid wash. Rinse thoroughly with clean water every hour after the acid releases and observe the surface. This cycle should generally be repeated three times, until the surface develops a metallic luster. For the acid wash, consider using a mixture of hydrofluoric acid, hydrochloric acid, and nitric acid in a weight ratio of 1.13:2.37:4.2.

[0035] S33: performing a first intermediate annealing treatment on the product after pickling treatment by using the first annealing process to eliminate the internal stress of the product; In this step, the vacuum degree is considered to be ≤3.0×10 -3 The temperature was raised to 1350°C within 70 min, then kept at this temperature for 90 min and then cooled to less than 80°C before being taken out of the furnace. No argon was added during the cooling process.

[0036] S34: heating the product after the first intermediate annealing treatment to 1300-1700° C. using a medium frequency induction furnace, and drawing and forging the product to a first preset length; This step is intended to perform free forging. Specifically, a medium frequency induction furnace is used to heat the product obtained in step S33 to 1300-1700°C, and then a hammer is used to stretch and forge the product to a length of not less than 700mm.

[0037] S35: heating the product after the drawing forging to 1050-1150° C. in a box furnace, and radially forging the product to a first preset diameter; This step is intended to perform radial forging. Specifically, a box furnace is used to heat the product obtained in step S34 to 1050-1150° C., and then forged to a diameter of φ40-45 mm.

[0038] S36: Pickling the radially forged product until the surface of the product presents a metallic luster; In this step, it is considered to perform pickling treatment on the radially forged product. For the specific pickling process, please refer to step S32.

[0039] S37: performing a second intermediate annealing treatment on the product after the pickling treatment using the first annealing process to eliminate the internal stress of the product; This step is intended to perform a second intermediate annealing process. For a specific annealing process, please refer to the first intermediate annealing process in step S33.

[0040] S38: sawing the product after the second intermediate annealing treatment into a second preset length, and machining it to a second preset diameter; In this step, the product obtained after the second intermediate annealing treatment is sawn into a length of 800~1000mm, and then the forging defects are removed by machining and turning the surface. The reference diameter after machining is φ36~φ38mm.

[0041] S39: The machined product is subjected to rotary forging to a target diameter to obtain a third alloy product.

[0042] In this step, the product is processed to a target diameter of φ13 mm by rotary swaging.

[0043] For step 4, consider heating the product to 1200-1450°C at a rate of 18-20°C / min, then holding the temperature for 60-120 minutes before cooling it to below 80°C before removing it from the furnace for final annealing, thereby obtaining the final high-strength niobium alloy. Prior to the final annealing process in step 4, consider pickling the third alloy product obtained in step 3. The pickling solution used is the same as that used in steps S32 and S36. Specifically, the product can be soaked or rinsed in the pickling solution for 10 minutes, then rinsed with clean water before final annealing.

[0044] The selection of annealing temperature for the finished product processing of this solution is described below with reference to specific embodiments.

[0045] Prepare samples A1, A2, B1, B2, C1, C2, D1, D2, E1, and E2 as follows: (1) Mix the powders according to the preferred ratio of 6 tantalum, 6 tungsten, 2 molybdenum, 1 zirconium and 0.08 carbon; (2) Using vacuum electron beam melting and water-cooled crucible casting to form ingots; (3) Sawing according to φ200~φ210×400~550mm; (4) Make an R20 arc chamfer on one end of the extrusion; (5) Using a process of keeping the temperature at 1350℃~1450℃ for 60~120min, the product after the arc chamfer is subjected to homogenization heat treatment; (6) Use a box-type resistance furnace to preheat to 80~120℃, then spray graphite emulsion, high-temperature glass powder and an appropriate amount of glass glue or water glass mixture on the surface and brush it evenly. The thickness of the coating is generally 0.3~0.6mm; (7) A medium frequency induction furnace is used for heating, and insulation platforms are designed at 800℃, 1000℃, 1100℃ and 1200℃~1300℃. The insulation time at 800℃, 1000℃, 1100℃ and 1200℃~1300℃ is 10 minutes.

[0046] (8) The conversion time is no more than 50 seconds, the extrusion speed is 80 mm / s, the extrusion temperature is 1200~1350℃, and the extrusion breakthrough pressure is 25~34MN; the extrusion die and the extrusion barrel need to be preheated to 500℃ in advance, and the extrusion die is filled with glass pads for lubrication, and the extrusion barrel is mixed with graphite, graphite emulsion, molybdenum disulfide and grease for spray lubrication, and the product is extruded into φ118~φ128mm.

[0047] (9) After the extruded product is sawn and shrunken, it is polished; (10) Use pickling solution to soak and pickle the surface. Rinse with clean water every hour to remove the acid. Repeat this process three times. The pickling solution is prepared by mixing hydrofluoric acid, hydrochloric acid, and nitric acid in a weight ratio of 1.13:2.37:4.2.

[0048] (11) When the vacuum degree is ≤3.0×10 -3 The temperature was raised to 1350°C within 70 min, then kept at this temperature for 90 min and then cooled to less than 80°C before being taken out of the furnace. No argon was added during the cooling process.

[0049] (12) Use a medium frequency induction furnace to heat the product to 1300~1700℃, and then use a hammer to stretch and forge the product to a length of not less than 700mm.

[0050] (13) The product is heated to 1050~1150℃ in a box furnace and then forged to a diameter of φ40~45mm.

[0051] (14) Perform pickling treatment, see step (10) for details.

[0052] (15) Perform the second annealing treatment. For the specific process, see (11).

[0053] (16) Cutting length up to 800~1000mm (17) Machined to a diameter of 38 mm.

[0054] (18) Rotate and forge to a diameter of 13 mm.

[0055] (19) Use pickling solution to pickle for 10 minutes and rinse with clean water.

[0056] (20) The samples were heated to 1450℃, 1400℃, 1350℃, 1250℃ and 1100℃ at a heating rate of 18~20℃ / min and kept at this temperature for 100min for finished product annealing treatment to obtain samples A1, A2, B1, B2, C1, C2, D1, D2, E1 and E2. Among them, A1 and A2 were samples treated at 1450℃, B1 and B2 were samples treated at 1400℃, C1 and C2 were samples treated at 1350℃, D1 and D2 were samples treated at 1250℃, and E1 and E2 were samples treated at 1100℃.

[0057] The mechanical strength test was carried out on each sample, and the test results are shown in Table 1 below: Table 1

[0058] The samples at different temperatures were selected for metallographic test, and the test results are shown in Table 2 below: Table 2

[0059] In Table 1 above, Rm is tensile strength, Rp0.2 is yield strength, and A is elongation. For high-strength niobium alloys, the tensile strength must be greater than 520, fully crystallized, and the elongation must be greater than 25. See Table 2, and also see Figure 2-6 As shown in the metallographic images (A1-E1), only annealing temperatures of 1400°C and 1450°C achieve good crystallization during the final product annealing process. Furthermore, considering the test results of tensile strength, yield strength, and elongation, it is clear that a final product annealing temperature of 1400°C achieves the best results.

[0060] Furthermore, the test results of the above embodiment are compared with the performance test results of Nb521 in the traditional solution.

[0061] The tensile strength of the conventional Nb521 alloy at room temperature is 400-450 MPa, the yield strength is 270-300 MPa, and the elongation is 20-24. Clearly, the strength of the high-strength niobium alloy obtained in this solution is significantly improved compared to the high-strength niobium alloy obtained based on this solution.

[0062] The modules or units in the apparatus of the embodiments of the present invention may be combined, divided, or deleted as needed. The above disclosure is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Persons skilled in the art will appreciate that any equivalent variations made by implementing all or part of the processes of the above embodiments in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for processing a high-strength niobium alloy, characterized in that: The following steps are involved: Step 1, ingot preparation: using niobium, tungsten, tantalum, molybdenum, zirconium and carbon to mix powder and cast an ingot to obtain a first alloy product; Step 2, extrusion processing: heating the first alloy product using a medium frequency induction furnace and extruding it using an extrusion ingot feeder to obtain a second alloy product; Step 3, forging: In the forging process, the first annealing process is used to perform two intermediate annealing treatments on the extruded second alloy product to obtain a third alloy product; wherein, the alloy product is subjected to free forging between the two intermediate annealing treatments; Step 4, finished product processing: The third alloy product is subjected to finished product annealing treatment using a second annealing process to obtain a final high-strength niobium alloy; wherein the second annealing process is: heating to 1200-1450°C at 18-20°C / min and holding at that temperature for 60-120 minutes.

2. The method for processing a high-strength niobium alloy according to claim 1, wherein: The ingot preparation process of step 1 specifically includes: S11: Mixing, sintering and melting niobium, tungsten, tantalum, molybdenum, zirconium and carbon as raw materials; S12: vacuum electron beam melting and water-cooled crucible casting to form ingots; S13: sawing the cast ingot according to preset specifications; S14: The sawn product is rounded to reduce the extrusion breakthrough pressure and prevent damage to the extrusion die; S15: A process of keeping the temperature at 1350℃~1450℃ for 60~120min is used to perform homogenization heat treatment on the product after the arc chamfer to obtain the first alloy product, so as to eliminate the casting stress and improve the plasticity and strength of the material by precipitating secondary relative materials.

3. The method for processing a high-strength niobium alloy according to claim 2, wherein: In step S11, the mass percentage of tantalum is (6-7)%, the mass percentage of tungsten is (6-7)%, the mass percentage of molybdenum is (1.7-2.3)%, the mass percentage of zirconium is (0.9-1.2)%, the mass percentage of carbon is (0.05-0.12)%, and the remainder is niobium.

4. The method for processing a high-strength niobium alloy according to claim 1, wherein: The extrusion process of step S2 specifically includes: S21: uniformly coating an anti-oxidation coating on the surface of the first alloy product; S22: Using a medium frequency induction furnace, a multi-temperature gradient heating process is used to extrusion heat the product after applying the anti-oxidation coating; S23: The extruded and heated product is transferred to an extrusion ingot feeder for extrusion to obtain a second alloy product.

5. The method for processing a high-strength niobium alloy according to claim 4, wherein: In step S22, the product coated with the anti-oxidation coating is extruded and heated using a multi-temperature gradient heating process, including: Insulation platforms at 800°C, 1000°C, 1100°C and 1200°C~1300°C are designed to heat the products coated with the antioxidant coating from low temperature to high temperature in sequence; the total heating time is 30~45 minutes, and the insulation time at 1200°C~1300°C is 2~10 minutes.

6. The method for processing a high-strength niobium alloy according to claim 4, wherein: The extrusion parameters in step S23 include: The conversion time is no more than 50 seconds, the extrusion speed is 40~120mm / s, the extrusion temperature is 1200~1350℃, and the extrusion breakthrough pressure is 25~34MN; the extrusion die and extrusion barrel need to be preheated to 350-650℃ in advance, and the extrusion die is filled and lubricated with glass pads, and the extrusion barrel is sprayed with a mixture of graphite, graphite emulsion, molybdenum disulfide and grease for lubrication.

7. The method for processing a high-strength niobium alloy according to claim 1, wherein: The forging process of step 3 specifically includes: S31: sawing and shrinking the second alloy product and then grinding it to remove defects on the extrusion surface; S32: Pickling the polished product to give the surface of the product a metallic luster; S33: performing a first intermediate annealing treatment on the product after pickling treatment by using the first annealing process to eliminate the internal stress of the product; S34: heating the product after the first intermediate annealing treatment to 1300-1700° C. using a medium frequency induction furnace, and drawing and forging the product to a first preset length; S35: heating the product after the drawing forging to 1050-1150° C. in a box furnace, and radially forging the product to a first preset diameter; S36: Pickling the radially forged product until the surface of the product presents a metallic luster; S37: performing a second intermediate annealing treatment on the product after the pickling treatment using the first annealing process to eliminate the internal stress of the product; S38: sawing the product after the second intermediate annealing treatment into a second preset length, and machining it to a second preset diameter; S39: The machined product is subjected to rotary forging to a target diameter to obtain a third alloy product.

8. The method for processing a high-strength niobium alloy according to claim 7, wherein: The first annealing process is: in a vacuum degree not greater than 3.0×10 -3 Pa, and then the temperature was raised to 1350±10°C within 70 minutes. After keeping the temperature for 90±5 minutes, the temperature was lowered to less than 80°C and the furnace was taken out. No argon gas was added during the cooling process.

9. The method for processing a high-strength niobium alloy according to claim 7, wherein: Prior to the finished product processing in step 4, the third alloy product is pickled.

10. The method for processing a high-strength niobium alloy according to claim 9, wherein: The pickling solution for pickling treatment is prepared from hydrofluoric acid, hydrochloric acid and nitric acid in a mass ratio of 1.13:2.37:4.2; wherein, the pickling process of step S32 and step S36 is: immersing the product in the pickling solution, and rinsing with clean water every hour until the surface of the product shows a metallic luster; the pickling time for the third product is 10 minutes.

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