A processing method of low-cost high-performance tantalum alloy plate

Abstract

The application discloses a processing method of low-cost high-performance tantalum alloy plate, which comprises the following steps: using a firm electrode obtained by uniformly mixing Ta powder, W powder and Nb powder and then welding as raw material, carrying out twice electron beam melting to obtain a large-size tantalum alloy ingot; through primary extrusion on the large-size ingot, repeated operations of turnover forging and shaping and secondary extrusion, a three-time extruded rod blank is obtained; finally, the extruded rod blank is subjected to blanking, intermediate annealing, cross-rolling and product annealing, and the preparation of the tantalum alloy plate is completed. The application uses Nb to replace part of the Ta matrix to prepare a new type of tantalum alloy, and the raw material cost can be reduced by about 1 / 4. Then, through multiple turnover forging and extrusion, cross-extrusion of the ingot is realized, the advantages of shear deformation and dislocation interlacing on grain crushing are fully utilized, the grain size of the prepared plate is above 8.0, and the mechanical properties are better than those of a traditional Ta2.5W alloy, so that the plate can be used as a preferred material for weapon equipment structural parts.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of non-ferrous metal material processing, and particularly relates to a processing method of low-cost high-performance tantalum alloy plate. BACKGROUND

[0002] Metal tantalum (Ta) is widely used in the chemical industry due to its good corrosion resistance, and is gradually replacing copper and tungsten to become the most ideal structural material of combat weapon equipment, such as anti-tank missile shell and tactical missile air vane, because of its high density (16.6 g / cm 3 ), high penetration performance, high strength, high temperature erosion resistance and good ductility. Among them, Ta2.5W alloy, as a kind of tantalum alloy, can improve the tensile strength by about 30% to about 340 MPa while maintaining the good plasticity of pure Ta, and the elongation is greater than 40%. The plate processed from the alloy has become the main material for the structural parts of the weapon equipment at the present stage in China.

[0003] Experiments show that the damage effect of Ta2.5W weapon equipment structural parts has a close relationship with the grain size, grain uniformity and mechanical property anisotropy of the plate. In order to reduce the grain size and improve the uniformity of the structure and mechanical properties, the previous researches are mostly focused on the grain breaking means of the ingot and the rolling method of the plate. Patent CN103243285B and patent CN104789912B adopt multi-upset and elongation type forging to break the grains of the tantalum alloy ingot, and then cross-rolling or unidirectional rolling is performed to obtain a plate with relatively uniform performance. However, due to the characteristics of the coarse columnar grains and high density of the tantalum alloy ingot, the existing process has two limitations: one is that the conventional forging has insufficient forging penetration, which leads to uneven grain distribution in different parts of the plate and unstable service performance, and the other is that the upsetting and elongation forging will cause serious folding and cracking defects on the surface of the ingot, which seriously affects the yield of the tantalum alloy and increases the processing cost. Moreover, if the grain uniformity of the forged plate blank is not thoroughly improved, it is difficult to prepare a plate with high quality, fine grains and no preferred orientation by unidirectional rolling, cross-rolling or circumferential rolling, which will cause the inconsistent nucleation time of dynamic recrystallization in different parts of the plate under high strain rate, poor damage effect, and become a technical problem to be solved at present. In addition, with the need of military attack test in recent years, the consumption of Ta2.5W plate has increased dramatically, and its expensive price (more than 5000 yuan / kg) and the special working condition of combat weapons make it difficult to recover, which brings great economic pressure to the procurement of Ta2.5W, and therefore the demand for low-cost and high-performance new tantalum alloy materials has become a research focus at present. SUMMARY

[0004] The technical problems to be solved by the present application are to provide a low-cost high-performance tantalum alloy plate processing method to solve the above problems of the prior art.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a low-cost high-performance tantalum alloy plate processing method, characterized in that it comprises the following steps:

[0006] Step one, electrode preparation: uniformly mix Ta powder, W powder and Nb powder, and combine and weld the formed electrode to obtain a firm electrode;

[0007] Step two, primary electron beam melting: melt the firm electrode in the electron beam melting furnace to obtain a primary melting ingot;

[0008] Step three, secondary electron beam melting: melt the primary melting ingot in the electron beam melting furnace again to obtain a secondary melting ingot;

[0009] Step four, primary extrusion: extrude the secondary melting ingot, and then cut to size to obtain a primary extruded rod blank;

[0010] Step five, forging and shaping: flip the primary extruded rod blank to obtain a large-size forged rod blank;

[0011] Step six, secondary extrusion: extrude the large-size forged rod blank to obtain a secondary extruded rod blank;

[0012] Step seven, repeat steps five and six to complete the uniformization and crushing of the tantalum alloy ingot grains to obtain a tertiary extruded rod blank;

[0013] Step eight, blanking: cut the tertiary extruded rod blank along the length direction to obtain a round thick plate blank;

[0014] Step nine, intermediate annealing: place the round thick plate blank in a vacuum annealing furnace for recrystallization annealing to obtain an annealed round thick plate blank;

[0015] Step ten, cross-rolling: remove the surface defects of the annealed round thick plate blank, and then cross-rolling to obtain a finished thickness plate;

[0016] Step eleven, product annealing: the product thickness plate in step ten is placed in a vacuum annealing furnace for recrystallization annealing, to obtain the product tantalum alloy plate.

[0017] The processing method of the low-cost high-performance tantalum alloy plate, characterized in that the purity of the Ta powder, W powder and Nb powder in step one is greater than 99.95%, the weight ratio of the Ta powder, W powder and Nb powder is 27:1:12, and the welding adopts plasma welding.

[0018] The processing method of the low-cost high-performance tantalum alloy plate, characterized in that the specification of the primary smelting ingot in step two is Φ280mm-Φ360mm, the smelting power is 800kW-1000kW, the smelting rate is 80kg / h-140kg / h, and the vacuum degree is less than 1.0×10 -2 Pa; the specification of the secondary smelting ingot in step three is the same as that of the primary smelting ingot, the smelting power is 750kW-950kW, the smelting rate is 150kg / h-250kg / h, and the vacuum degree is less than 1.0×10 -2 Pa.

[0019] The processing method of the low-cost high-performance tantalum alloy plate, characterized in that the extrusion direction of the extrusion in step four is the length direction of the ingot, the extrusion temperature is room temperature, the extrusion ratio is 4.0, the diameter of the primary extrusion rod blank is Φ140mm-Φ180mm, and the length of the sawing to the specified size is 4.0 times the diameter of the rod blank.

[0020] The processing method of the low-cost high-performance tantalum alloy plate, characterized in that the temperature of the turnover forging in step five is room temperature, the length direction of the extrusion rod blank is taken as the diameter direction after forging, and the diameter direction of the extrusion rod blank is taken as the height direction after forging, and the diameter of the large-size forged rod blank is consistent with the diameter of the secondary smelting ingot in step three.

[0021] The processing method of the low-cost high-performance tantalum alloy plate, characterized in that the extrusion direction of the extrusion in step six is the length direction of the large-size forged rod blank, the extrusion temperature is room temperature, the extrusion ratio is 4.0, and the diameter of the secondary extrusion rod blank is Φ140mm-Φ180mm.

[0022] The processing method of the low-cost high-performance tantalum alloy plate, characterized in that the thickness of the round thick plate blank in step eight is 60mm-100mm, and the diameter is Φ140mm-Φ180mm.

[0023] The processing method of the low-cost high-performance tantalum alloy plate has the characteristics that the recrystallization annealing temperature in the ninth step is 1300-1400 DEG C, the holding time is 90-150 min, and the vacuum degree is less than 2.0*10 -2 Pa.

[0024] The processing method of the low-cost high-performance tantalum alloy plate has the characteristics that the cross-rolling in the tenth step is room temperature rolling, the rolling direction is rotated clockwise by 50 DEG in the previous rolling direction, eight passes are one cycle of rolling, the thickness of the plate is 4-10 mm after one to three cycles of rolling, and the total processing rate is not less than 90%.

[0025] The processing method of the low-cost high-performance tantalum alloy plate has the characteristics that the recrystallization annealing temperature in the eleventh step is 1250-1350 DEG C, the holding time is 60-120 min, and the vacuum degree is less than 2.0*10 - 2 Pa.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] 1. The present application creatively uses pure Nb to replace the nominal 30% pure Ta matrix to prepare a new type of tantalum alloy, which benefits from the fact that the price of pure Nb is only about one fifth of that of pure Ta, so that the material cost of the new type of tantalum alloy per kilogram is reduced by about 1 / 4 compared with the traditional Ta2.5W, thereby reducing the cost pressure of large-scale procurement of plates at the present stage. In addition, the metal niobium Nb not only plays a solid solution strengthening role in the tantalum matrix, but also can appropriately reduce the grain size of the smelted ingot, which is beneficial to subsequent plastic processing. Moreover, due to the advantages of being homologous with Ta and small density, the plasticity of the new type of tantalum alloy material not only does not decrease, but also can increase to a certain extent.

[0028] 2. In the ingot preparation process of the present application, the high-power, low-melting-speed and large-size method is adopted in the first electron beam smelting, so as to ensure that the molten pool is deep, wide and has high metal activity, and the alloy elements have enough time and kinetic energy for uniform mixing, so as to obtain an alloy ingot with uniform composition and extremely low impurity content; the low-power, high-melting-speed and large-size method is adopted in the second electron beam smelting, so as to make the superheat degree of the molten pool small, accelerate the metal solidification speed, and reduce the generation of super-large grains, which is beneficial to the control of the grain size difference of the mold cover material.

[0029] 3、For ingot grain breakage, the present application reverses the extruded rod by 90° to restore the original ingot diameter, i.e. the diameter of the extruded rod becomes length, and the length becomes diameter, and then re-extrusion is performed, and so on, to realize cross-extrusion deformation of the ingot. Compared with the traditional upsetting and elongation deformation which is not deep, the cross-extrusion not only has accumulation of large strain, but also is mainly large shear deformation with many dislocations, so that the as-cast grains can be uniformly and severely deformed in multiple directions, and large-angle grain boundaries are easily formed, so that the grain nucleation position is increased during recrystallization annealing, and the grain refinement effect is most obvious, which is crucial for reducing the grain size of tantalum alloy structural parts. It is worth mentioning that the cross-extrusion deformation effectively weakens the preferred orientation of the original ingot grain (the <100> direction of the grain is parallel to the length of the ingot), which can reduce the mechanical property anisotropy caused by the microstructure.

[0030] 4、The present application can reduce the performance difference of the plate in different directions by cyclic cross-rolling of the round thick slab of the extruded rod, which is helpful for the symmetrical forming of structural parts.

[0031] 5、The Ta2.5W plate prepared by the conventional upsetting and elongation forging combined with rolling process generally has a tensile strength of 300MPa-370MPa, a yield strength of 220-280MPa, and an elongation of 40%-60%, and there is performance fluctuation or unevenness. The tantalum alloy plate prepared by the processing method of the present application has a tensile strength of 370MPa or more, a yield strength of 270MPa or more, and an elongation of 60% or more, and has uniform and fine structure, an average grain size of less than 22.5μm, a grain size of more than 8.0 levels and no level difference in different parts, and comprehensive performance comparable to or even better than the current Ta2.5W plate, which is suitable for the selection of tantalum alloy structural parts for current weapons and equipment.

[0032] The technical solutions of the present application will be further described in detail below in combination with the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a process flow diagram of the present application.

[0034] Figure 2 It is a metallographic structure diagram of the 4mm plate prepared in Example 1 of the present application.

[0035] Figure 3 It is a metallographic structure diagram of the 7mm plate prepared in Example 2 of the present application.

[0036] Figure 4 It is a metallographic structure diagram of the 10mm plate prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0037] Example 1

[0038] The embodiment provides a processing method of low-cost high-performance tantalum alloy plate material, the thickness of the plate material is 4mm, and a process flow is as shown in the figure, and the process flow specifically comprises the following steps. Figure 1

[0039] Step one, electrode preparation: Ta powder, W powder and Nb powder with a purity greater than 99.95% are uniformly mixed according to a weight ratio of 27:1:12, are combined after forming, and are subjected to plasma welding to obtain a firm electrode;

[0040] Step two, primary electron beam melting: the firm electrode obtained in step one is subjected to melting in an electron beam melting furnace, wherein the ingot specification is Φ280mm, the melting power is 800kW, the melting rate is 80kg / h, and the vacuum degree is less than 1.0*10 -2 Pa, and a primary melting ingot is obtained;

[0041] Step three, secondary electron beam melting: the primary melting ingot obtained in step two is subjected to secondary melting in the electron beam melting furnace, wherein the specification of the secondary melting ingot is the same as that of the primary melting, that is, Φ280mm, the melting power is 750kW, the melting rate is 150kg / h, and the vacuum degree is less than 1.0*10 -2 Pa.

[0042] A secondary melting ingot is obtained;

[0043] Step four, primary extrusion: the Φ280mm ingot obtained in step three is subjected to extrusion and sawing, wherein the extrusion direction is the length direction of the ingot, the extrusion temperature is room temperature, and the extrusion ratio is 4.0, so that a primary extrusion rod blank with a diameter of Φ140mm and a length of 560mm is obtained;

[0044] Step five, forging shaping: the extrusion rod blank obtained in step four is subjected to room-temperature upset forging, the length direction of the extrusion rod blank is taken as the diameter direction after forging, the diameter direction of the extrusion rod blank is taken as the height direction after forging, that is, the axial direction of the rod blank is turned by 90°, and a large-size forged rod blank with a diameter of Φ280mm is obtained by forging;

[0045] Step six, secondary extrusion: the large-size forged rod blank obtained in step five is subjected to extrusion, the extrusion direction is the length direction of the large-size forged rod blank, the extrusion temperature is room temperature, the extrusion ratio is 4.0, and a secondary extrusion rod blank with a diameter of Φ140mm is obtained;

[0046] Step seven, repeating steps five to six, the tantalum alloy ingot grain is uniformly broken, and a tertiary extrusion rod blank with a diameter of Φ140mm is obtained;

[0047] ​Step eight, blanking: the extruded rod blank obtained in step seven is sawed along the length direction according to 60mm to obtain a circular thick slab with a thickness of 60mm and a diameter of 140mm;

[0048] Step nine, intermediate annealing: the circular thick slab obtained in step eight is placed in a vacuum annealing furnace for recrystallization annealing, the temperature is 1300℃, the holding time is 90min, the vacuum degree is less than 2.0x10 -2 Pa, to obtain an annealed circular thick slab;

[0049] Step ten, cross-rolling: the annealed circular thick slab obtained in step nine is cleaned to remove surface defects, and then cross-rolled, wherein the cross-rolling is room temperature rolling, each pass rolling direction is rotated clockwise by 50° along the direction of the previous pass, wherein 8 passes are 1 cycle of rolling, after 1 cycle of rolling, a finished thickness plate with a thickness of 4mm is obtained, and the total processing rate is 93%;

[0050] Step eleven, finished product annealing: the finished thickness plate obtained in step ten is placed in a vacuum annealing furnace for recrystallization annealing, the temperature is 1250℃, the holding time is 60min, the vacuum degree is less than 2.0x10 -2 Pa, to obtain a low-cost high-performance tantalum alloy plate.

[0051] The metallographic diagram of the tantalum alloy plate obtained in this embodiment is shown in Figure 2 As can be seen from Figure 2 , the internal structure of the plate is uniform, and the grain size is small, the average grain size is about 9.4μm, the grain size is 10.5 levels and has no level difference. The room temperature mechanical properties are tested, the tensile strength is 398MPa, the yield strength is 302MPa, and the elongation is 64%.

[0052] Example 2

[0053] This embodiment provides a processing method of a low-cost high-performance tantalum alloy plate, the thickness of the plate is 7mm, and the process flow is shown in Figure 1 , and specifically includes the following steps:

[0054] Step one, electrode preparation: Ta powder, W powder and Nb powder with a purity of more than 99.95% are uniformly mixed according to a weight ratio of 27:1:12, formed into a combination, and then welded by plasma to obtain a firm electrode;

[0055] Step two, primary electron beam melting: the firm electrode obtained in step one is melted in an electron beam melting furnace, wherein the ingot specification is Φ320mm, the melting power is 900kW, the melting rate is 110kg / h, and the vacuum degree is less than 1.0x10 -2 Pa, to obtain a primary melting ingot;

[0056] Step three, secondary electron beam melting: the primary melting ingot obtained in step two is subjected to secondary melting in an electron beam melting furnace, wherein the specification of the secondary melting ingot is the same as that of the primary melting, i.e., Φ320 mm, the melting power is 850 kW, the melting rate is 200 kg / h, and the vacuum degree is less than 1.0×10 -2 Pa.

[0057] to obtain a secondary melting ingot;

[0058] Step four, primary extrusion: the Φ320 mm ingot obtained in step three is subjected to extrusion and sawing, wherein the extrusion direction is the length direction of the ingot, the extrusion temperature is room temperature, and the extrusion ratio is 4.0, to obtain a primary extruded rod blank with a diameter of Φ160 mm and a length of 640 mm;

[0059] Step five, forging shaping: the extruded rod blank obtained in step four is subjected to room temperature upset forging, wherein the length direction of the extruded rod blank, i.e., 640 mm, is taken as the diameter direction after forging, and the diameter direction of the extruded rod blank, i.e., Φ160 mm, is taken as the height direction after forging, i.e., the axial direction of the rod blank is turned by 90°, to obtain a large-size forged rod blank with a diameter of Φ320 mm;

[0060] Step six, secondary extrusion: the large-size forged rod blank obtained in step five is subjected to extrusion, wherein the extrusion direction is the length direction of the large-size forged rod blank, the extrusion temperature is room temperature, and the extrusion ratio is 4.0, to obtain a secondary extruded rod blank with a diameter of Φ160 mm;

[0061] Step seven, repeating steps five to six, to complete the uniformization and fragmentation of the grains of the tantalum alloy ingot, to obtain a tertiary extruded rod blank with a diameter of Φ160 mm;

[0062] Step eight, blanking: the extruded rod blank obtained in step seven is sawed along the length direction according to 80 mm, to obtain a circular thick slab blank with a thickness of 80 mm and a diameter of Φ160 mm;

[0063] Step nine, intermediate annealing: the circular thick slab blank obtained in step eight is placed in a vacuum annealing furnace for recrystallization annealing, wherein the temperature is 1350℃, the holding time is 120 min, and the vacuum degree is less than 2.0×10 -2 Pa, to obtain an annealed circular thick slab blank;

[0064] Step ten, cross-rolling: the annealed circular thick slab blank obtained in step nine is cleaned to remove surface defects, and then subjected to cross-rolling, wherein the cross-rolling is room temperature rolling, and the rolling direction is rotated clockwise by 50° along the direction of the previous pass, wherein 8 passes constitute one cycle of rolling, and after 2 cycles of rolling, a finished thickness plate with a thickness of 7 mm is obtained, and the total processing rate is 91%;

[0065] Step 11, Finished Product Annealing: The finished thickness plate obtained in Step 10 is placed in a vacuum annealing furnace for recrystallization annealing at a temperature of 1300℃ for 90 minutes, with a vacuum degree of less than 2.0 × 10⁻⁶. -2 Pa yields low-cost, high-performance tantalum alloy plates.

[0066] The metallographic image of the tantalum alloy plate obtained in this embodiment is as follows: Figure 3 As shown, according to Figure 3 It can be seen that the internal structure of the board is uniform and the grains are fine, with an average grain size of about 13.3 μm and a grain size of grade 9.5 with no grade difference. The room temperature mechanical properties were tested and found to be a tensile strength of 386 MPa, a yield strength of 285 MPa, and an elongation of 65%.

[0067] Example 3

[0068] This embodiment provides a low-cost, high-performance tantalum alloy plate processing method. The plate thickness is 10mm, and the process flow is as follows: Figure 1 As shown, the specific steps include:

[0069] Step 1, Electrode preparation: Mix Ta powder, W powder and Nb powder with a purity greater than 99.95% in a weight ratio of 27:1:12, shape them and assemble them, and then obtain a strong electrode by plasma welding.

[0070] Step 2, Primary Electron Beam Melting: The robust electrode obtained in Step 1 is melted in an electron beam melting furnace. The ingot size is Φ360mm, the melting power is 1000kW, the melting rate is 140kg / h, and the vacuum degree is less than 1.0×10⁻⁶. -2 Pa, obtained from a single smelting and casting of an ingot;

[0071] Step 3, Secondary Electron Beam Melting: The primary smelted ingot obtained in Step 2 is remelted in an electron beam melting furnace. The secondary smelted ingot has the same specifications as the primary smelted ingot, Φ360mm, with a melting power of 950kW, a melting rate of 250kg / h, and a vacuum degree of less than 1.0×10⁻⁶. -2 Pa.

[0072] Obtain secondary smelting and casting of ingots;

[0073] Step 4, Primary Extrusion: The Φ360mm ingot obtained in Step 3 is extruded and sawn, with the extrusion direction being the length of the ingot, the extrusion temperature being room temperature, and the extrusion ratio being 4.0, to obtain a primary extruded billet with an extrusion diameter of Φ180mm and a length of 720mm.

[0074] Step five, forging shaping: the extruded rod blank obtained in step four is subjected to room temperature upset forging, the length direction of the extruded rod blank is taken as the diameter direction after forging, the diameter direction of the extruded rod blank is taken as the height direction after forging, that is, the axial direction of the rod blank is turned by 90°, and a large-size forged rod blank with a diameter of Φ360 mm is obtained by forging;

[0075] Step six, extrusion again: the large-size forged rod blank obtained in step five is subjected to extrusion, the extrusion direction is the length direction of the large-size forged rod blank, the extrusion temperature is room temperature, the extrusion ratio is 4.0, the diameter of the twice-extruded rod blank is Φ180 mm, and a twice-extruded rod blank is obtained;

[0076] Step seven, repeating steps five to six, to complete the uniformization and crushing of the tantalum alloy ingot grains, and a three-times-extruded rod blank with a diameter of Φ180 mm is obtained;

[0077] Step eight, cutting: the extruded rod blank obtained in step seven is cut along the length direction according to 100 mm, and a circular thick slab blank with a thickness of 100 mm and a diameter of Φ180 mm is obtained;

[0078] Step nine, intermediate annealing: the circular thick slab blank obtained in step eight is placed in a vacuum annealing furnace for recrystallization annealing, the temperature is 1400℃, the holding time is 150 min, the vacuum degree is less than 2.0×10 -2 Pa, and an annealed circular thick slab blank is obtained;

[0079] Step ten, cross rolling: the annealed circular thick slab blank obtained in step nine is cleaned to remove surface defects, and then is subjected to cross rolling, wherein the cross rolling is room temperature rolling, each pass rolling direction is rotated clockwise by 50° along the direction of the previous pass, wherein 8 passes are 1 cycle of rolling, and after 3 cycles of rolling, a finished thickness plate with a thickness of 10 mm is obtained, and the total processing rate is 90%;

[0080] Step eleven, finished product annealing: the finished thickness plate obtained in step ten is placed in a vacuum annealing furnace for recrystallization annealing, the temperature is 1350℃, the holding time is 120 min, the vacuum degree is less than 2.0×10 -2 Pa, and a low-cost high-performance tantalum alloy plate is obtained.

[0081] The metallographic diagram of the tantalum alloy plate obtained in the embodiment is shown in Figure 4 As can be seen from Figure 4 , the internal structure of the plate is uniform, and the grains are fine, the average grain size is about 18.9 μm, the grain size is 8.5 grade and has no grade difference. The room temperature mechanical properties are tested, the tensile strength is 380 MPa, the yield strength is 279 MPa, and the elongation is 67%.

[0082] The above is only the preferred embodiment of the present application, and does not limit the present application, and any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical scheme of the present application.

Claims

1. A method for processing a low-cost high-performance tantalum alloy sheet material, characterized by, It comprises the following steps: Step one, electrode preparation: uniformly mix Ta powder, W powder and Nb powder, and combine and weld after forming to obtain a firm electrode; Step two, once electron beam smelting: the firm electrode described in step one is smelted in an electron beam smelting furnace, and a once smelted ingot is obtained; the specification of the once smelted ingot is Φ280mm~Φ360mm, the smelting power is 800kW~1000kW, the smelting rate is 80kg / h~140kg / h, and the vacuum degree is less than 1.0×10 -2 Pa; Step three, secondary electron beam melting: the primary melting ingot in step two is melted again in an electron beam melting furnace to obtain a secondary melting ingot; the secondary melting ingot has the same specification as the primary melting ingot, the melting power is 750 kW-950 kW, the melting rate is 150 kg / h-250 kg / h, the vacuum degree is less than 1.0 x 10 -2 Pa; Step four, primary extrusion: extrude the secondary melting ingot in step three, and then cut to size to obtain a primary extruded rod blank; the extrusion direction of the extrusion is the length direction of the ingot, the extrusion temperature is room temperature, the extrusion ratio is 4.0, the diameter of the primary extruded rod blank is Φ140mm~Φ180mm, and the length of the cut-to-size is 4.0 times the diameter of the rod blank; Step five, forging shaping: flip forging is performed on the primary extruded rod blank in step four to obtain a large-size forged rod blank; Step six, secondary extrusion: the large-size forged rod blank in step five is extruded to obtain a secondary extruded rod blank; Step seven, repeat steps five and six to complete the homogenization and crushing of the tantalum alloy ingot grains to obtain a tertiary extruded rod blank; Step eight, blanking: the tertiary extruded rod blank in step seven is cut along the length direction to obtain a round thick slab blank; Step nine, intermediate annealing: the round thick slab blank in step eight is placed in a vacuum annealing furnace for recrystallization annealing to obtain an annealed round thick slab blank; Step ten, cross-rolling: the surface defects of the annealed round thick slab blank in step nine are removed, and then cross-rolling is performed to obtain a finished thickness plate; Step eleven, finished product annealing: the finished thickness plate in step ten is placed in a vacuum annealing furnace for recrystallization annealing to obtain a finished tantalum alloy plate.

2. The method of claim 1, wherein the method is characterized by: The purity of the Ta powder, W powder and Nb powder in step one is greater than 99.95%, the weight ratio of the Ta powder, W powder and Nb powder is 27:1:12, and the welding adopts plasma welding.

3. The method of claim 1, wherein the method is characterized by: The temperature of the flip forging in step five is room temperature, the length direction of the extruded rod blank is taken as the diameter direction after forging, the diameter direction of the extruded rod blank is taken as the height direction after forging, and the diameter of the large-size forged rod blank is consistent with the diameter of the secondary melting ingot in step three.

4. The method of claim 1, wherein the method is characterized by: The extrusion direction of the extrusion in step six is the length direction of the large-size forged rod blank, the extrusion temperature is room temperature, the extrusion ratio is 4.0, and the diameter of the secondary extruded rod blank is Φ140mm~Φ180mm.

5. The method of claim 1, wherein the method is characterized by: The thickness of the round thick slab blank in step eight is 60mm~100mm, and the diameter is Φ140mm~Φ180mm.

6. The method of claim 1, wherein the method is characterized by: The temperature of the recrystallization annealing in step nine is 1300-1400℃, the holding time is 90-150 min, and the vacuum degree is less than 2.0x10 -2 Pa.

7. The method of claim 1, wherein the method is characterized by: The cross-rolling in step ten is room temperature rolling, the rolling direction is rotated clockwise by 50° along the direction of the previous pass, 8 passes are 1 cycle of rolling, a plate with a thickness of 4mm~10mm is obtained after 1~3 cycles of rolling, and the total processing rate is not less than 90%.

8. The method of claim 1, wherein the method is characterized by: The temperature of the recrystallization annealing in step eleven is 1250°C to 1350°C, the holding time is 60 min to 120 min, and the vacuum degree is less than 2.0 x 10 -2 Pa.

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