Nickel-based alloy and niobium-tungsten alloy welding method and welding assembly

Abstract

The invention provides a welding method and a welding assembly for a nickel-based alloy and a niobium-tungsten alloy. The welding method comprises the following steps that S1, a nickel-based alloy and a niobium-tungsten alloy are assembled and clamped to form a to-be-welded assembly; s2, a first vacuum electron beam welding process is adopted for conducting positioned welding on the to-be-welded assembly to obtain a positioned weldment, and the electron beam current for positioned welding is 20 mA to 30 mA; s3, a second vacuum electron beam welding process is adopted for conducting positioning welding on the to-be-welded assembly to obtain a formal weldment, electron beams for formal welding deviate towards the niobium-tungsten alloy, the beam deviation amount ranges from 0.2 mm to 0.3 mm, and the electron beam current ranges from 50 mA to 60 mA; and S4, the weldment is annealed after being cooled to the room temperature, and the annealing temperature ranges from 1100 DEG C to 1450 DEG C. According to the welding method, low-stress uniform fusion of the nickel-based alloy and the niobium-tungsten alloy is achieved on the whole, and the metallurgical compatibility and the service reliability of a welded joint are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal welding, and in particular to a welding method and a welding assembly for a nickel-based alloy and a niobium-tungsten alloy. Background Art

[0002] In fields such as aerospace, components place extremely high demands on the comprehensive performance of materials, especially in high-temperature, high-strength, and lightweight parts such as combustion chambers and turbine blades. How to achieve reliable connections between different high-temperature alloy materials has become a key technical challenge. Nickel-based high-temperature alloys are widely used in the above-mentioned key parts due to their excellent high-temperature oxidation resistance, creep strength, and impact resistance. However, their higher density limits the potential for further improving the engine thrust-to-weight ratio. In contrast, Nb521 alloy, as a medium-strength and plastic dispersion-strengthened niobium-tungsten refractory alloy, combines high melting point, low density, and good high-temperature mechanical properties, showing great advantages in aerospace weight reduction design.

[0003] Therefore, achieving high-quality welds between nickel-based superalloys and niobium-tungsten refractory alloys will help balance the high-temperature performance of the materials with the need for weight reduction. However, due to significant differences between the two materials in physical properties (such as melting point, thermal conductivity, and thermal expansion coefficient) and metallurgical behavior (such as element diffusion and reactivity), the welding process is prone to weld defects such as cracks, porosity, element segregation, and interface embrittlement, presenting a technical challenge in practical engineering.

[0004] Currently, various welding methods for high-temperature alloys have been reported. For example, Chinese patent application publication number CN112570876A discloses a vacuum electron beam welding method for GH4141 nickel-based superalloy. By adjusting welding parameters, it effectively reduces cracking and deformation, but does not address dissimilar joining with niobium-tungsten alloys. Chinese patent application publication number CN119260132A proposes electron beam welding technology for micron-scale nickel-based foil, which improves weld density but is still limited to homogeneous materials.

[0005] It can be seen that the existing technology fails to provide a reliable method for achieving high-quality welding connection between niobium-tungsten refractory alloy and nickel-based high-temperature alloy. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a welding method and welding assembly of nickel-based alloy and niobium-tungsten alloy.

[0007] In a first aspect of the present invention, a method for welding a base alloy and a niobium-tungsten alloy is provided, comprising the following steps:

[0008] S1, assembling and clamping the nickel-based alloy and the niobium-tungsten alloy to form a component to be welded;

[0009] S2, using a first vacuum electron beam welding process to perform tack welding on the assembly to be welded to obtain a tack weldment, wherein the electron beam current of the tack welding is 20mA-30mA;

[0010] S3, using the second vacuum electron beam welding process to perform positioning welding on the assembly to be welded to obtain a formal weldment, wherein the electron beam of the formal welding is offset toward the niobium tungsten alloy with a beam offset of 0.2 mm to 0.3 mm and an electron beam current of 50 mA to 60 mA;

[0011] S4, annealing the weldment after cooling it to room temperature, with the annealing temperature being 1100°C-1450°C.

[0012] In any embodiment of the first aspect, the first vacuum electron beam welding process and the second vacuum electron beam welding process each independently satisfy any one or more of the following conditions:

[0013] 1) Vacuum degree of welding chamber ≤10 -3 Pa;

[0014] 2) Accelerating voltage is 50kV-60kV;

[0015] 3) Welding speed is 400mm / min-600mm / min;

[0016] 4) Focusing current is 630mA-640mA.

[0017] In any embodiment of the first aspect, the electron beam focusing mode for both regular welding and tack welding is surface focusing.

[0018] In any embodiment of the first aspect, the surface roughness of the nickel-based alloy and the niobium-tungsten alloy to be welded is ≤0.3 μm, and the gap between the surfaces of the nickel-based alloy and the niobium-tungsten alloy to be welded after pairing is 1 mm-2 mm.

[0019] In any embodiment of the first aspect, during the cooling process of step S4, the pressure of the welding chamber for formal welding is increased at a rate of 0.5 Pa / min to 2 Pa / min.

[0020] In any embodiment of the first aspect, during the cooling process of step S4, gas is introduced into the welding chamber to cool and increase the pressure. Optionally, the gas includes at least one of argon and helium.

[0021] In any embodiment of the first aspect, the cooling rate is 10° C. / min-30° C. / min.

[0022] In any embodiment of the first aspect, the annealing treatment comprises: -8Pa vacuum environment, heat the cooled weldment to 1100℃-1450℃ and keep it warm for 0.5 h-1h.

[0023] In any embodiment of the first aspect, the niobium-tungsten alloy includes at least one of Nb521 and Nb6621 alloys, and / or the nickel-based high-temperature alloy includes at least one of GH4169, GH3044, and GH3625 alloys.

[0024] In its second aspect, the present invention provides a welded assembly comprising a niobium-tungsten alloy and a nickel-based alloy welded together. The welded assembly has a tensile strength of 330 MPa to 380 MPa and a hardness of 380 Hv to 480 Hv. These tensile strength and hardness demonstrate that the present invention achieves a high-strength metallurgical bond at the interface between the dissimilar materials of the niobium-tungsten alloy and the nickel-based alloy.

[0025] In any embodiment of the second aspect, the welded assembly is prepared using the welding method described in any embodiment of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 This is the macroscopic morphology of the weld in Example 1;

[0028] Figure 2 This is the macroscopic morphology of the weld in Example 2;

[0029] Figure 3 This is the microscopic morphology of the weld in Example 2. DETAILED DESCRIPTION

[0030] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0032] As described in the background art, the prior art fails to achieve high-quality welding connections between nickel-based high-temperature alloys and niobium-tungsten refractory alloys. To address this problem, the present invention provides a welding method and a welding assembly for nickel-based alloys and niobium-tungsten alloys.

[0033] A first embodiment of the present invention provides a method for welding a nickel-based alloy and a niobium-tungsten alloy, comprising the following steps:

[0034] S1, assembling and clamping the nickel-based alloy and the niobium-tungsten alloy to form a component to be welded;

[0035] S2, using a first vacuum electron beam welding process to perform tack welding on the assembly to be welded to obtain a tack weldment, wherein the electron beam current of the tack welding is 20mA-30mA;

[0036] S3, using the second vacuum electron beam welding process to perform positioning welding on the assembly to be welded to obtain a formal weldment, wherein the electron beam of the formal welding is offset toward the niobium tungsten alloy with a beam offset of 0.2 mm to 0.3 mm and an electron beam current of 50 mA to 60 mA;

[0037] S4, annealing the weldment after cooling it to room temperature, with the annealing temperature being 1100°C-1450°C.

[0038] In the above welding method, first, in S2, a relatively low electron beam current of 20mA-30mA is used to position weld the components to be welded. This step can not only make the surface of the material slightly melt, achieve temporary fixation, and suppress thermal deformation during formal welding, but also the low beam process controls the interface temperature below the eutectic point, which can suppress the generation of brittle phases from the source; in S3, the electron beam of the formal welding is offset by 0.2mm-0.3mm to the niobium tungsten alloy, which is conducive to balancing the heat distribution of the molten pool, avoiding overheating and melting loss of the nickel-based alloy, and ensuring that the high-melting-point niobium tungsten alloy is fully fused, and the 50mA-60mA electron beam current and the offset amount cooperate to regulate the molten pool convection, so that the molten pool composition tends to be uniform; finally, step S4 cools the material to below the recrystallization temperature and then anneals, which can suppress grain boundary reactions and reduce residual stress. The multi-stage temperature adjustment and coordinated optimization of welding parameters of the above technical solution achieve low-stress uniform fusion of nickel-based alloy and niobium tungsten alloy as a whole, significantly improving the metallurgical compatibility and service reliability of the welded joint.

[0039] In some embodiments, the electron beam current for tack welding may be 20 mA, 21 mA, 22 mA, 23 mA, 24 mA, 25 mA, 26 mA, 27 mA, 28 mA, 29 mA, 30 mA, or within a range between any two of the above values.

[0040] In some embodiments, the electron beam offset of the formal weld can be 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, 0.3 mm, or within the range of any two of the above values.

[0041] In some embodiments, the electron beam current for formal welding may be 50 mA, 51 mA, 52 mA, 53 mA, 54 mA, 55 mA, 56 mA, 57 mA, 58 mA, 59 mA, 60 mA, or within a range between any two of the above values.

[0042] In some embodiments, the annealing temperature may be 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C, or within a range between any two of the foregoing values.

[0043] In some embodiments, the surface roughness of the nickel-based alloy and the niobium-tungsten alloy to be welded is ≤ 0.3 μm. For example, the surface roughness of the nickel-based alloy and the niobium-tungsten alloy to be welded is independently 0.3 μm, 0.2 μm, 0.1 μm, or within the range of any two of the above values, or less than 0.1 μm. In some embodiments, the gap between the surfaces of the nickel-based alloy and the niobium-tungsten alloy to be welded after pairing is 1 mm to 2 mm. For example, the gap between the surfaces of the nickel-based alloy and the niobium-tungsten alloy to be welded after pairing can be 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, or within the range of any two of the above values. The combination of roughness and gap control can increase the contact area between the nickel-based alloy and the niobium-tungsten alloy, eliminating the risk of lack of fusion at the source.

[0044] The roughness of the surface to be welded in this invention can be measured as follows: Testing is performed at room temperature using a contact surface roughness meter (profilometer) in accordance with ISO 4287. Before measurement, the surface to be measured must be cleaned with anhydrous ethanol to remove oil and impurities. At least three different locations within the weld area are selected as measurement points. Five scans are performed perpendicular to the machined grain at each measurement point, and the arithmetic mean is taken as the Ra value for that point. The final roughness is the average of the Ra values ​​of all measurement points.

[0045] In some embodiments, in the first vacuum electron beam welding process and the second vacuum electron beam welding process, the vacuum degree of the welding chamber is independently ≤10 -3 Pa, for example, the vacuum degree of the welding chamber for the first vacuum electron beam welding and the second vacuum electron beam welding can be independently 0.8×10 -3 Pa, 0.6×10 -3 Pa, 0.4×10 -3Pa, 0.2×10 -3 Pa, 1×10 -4 Pa or within the range of any two of the above values, or less than 1×10 -4 In the first vacuum electron beam welding process, this higher vacuum environment prevents oxidation contamination of the micro-melting zone, ensuring the purity of the temporary joint surface. In the second vacuum electron beam welding process, this higher vacuum environment blocks the active oxidation of the niobium-tungsten alloy, prevents the precipitation of brittle nitrides, and inhibits the formation of weld porosity and oxide inclusions.

[0046] In some embodiments, the acceleration voltages of the first vacuum electron beam welding process and the second vacuum electron beam welding process are each independently 50 kV-60 kV. For example, the acceleration voltages of the first vacuum electron beam welding process and the second vacuum electron beam welding process can each independently be 50 kV, 51 kV, 52 kV, 53 kV, 54 kV, 55 kV, 56 kV, 57 kV, 58 kV, 59 kV, 60 kV, or within the range of any two of the above values. By controlling the acceleration voltage within the above range, the electron beam penetration depth can be controlled, and a temporary joint for positioning and a formal welding seam can be formed in the first vacuum electron beam welding process and the second vacuum electron beam welding process, respectively.

[0047] In some embodiments, the welding speeds of the first vacuum electron beam welding process and the second vacuum electron beam welding process are each independently 400 mm / min to 600 mm / min. For example, the welding speeds of the first vacuum electron beam welding process and the second vacuum electron beam welding process can each independently be 400 mm / min, 450 mm / min, 500 mm / min, 550 mm / min, 600 mm / min, or within a range of any two of the foregoing values. Welding speeds within the foregoing ranges can form a continuous molten pool while preventing local overheating, reducing eutectic reactions in the nickel-based alloy, and inhibiting the precipitation of intermetallic compounds.

[0048] In some embodiments, the focusing current of the first vacuum electron beam welding process and the second vacuum electron beam welding process is independently 630mA-640mA. For example, the focusing current of the first vacuum electron beam welding process and the second vacuum electron beam welding process can be independently 632mA, 634mA, 636mA, 638mA, 640mA, or within the range of any two of the above values. In vacuum electron beam welding, the focusing current determines the focusing degree and beam spot diameter of the electron beam, thereby affecting the energy density distribution. The focusing current within the above range can achieve the thermal field distribution required by the first and second vacuum electron beam welding processes without over-focusing to cause local evaporation, burning, or cracking.

[0049] In some embodiments, the electron beam focusing method for both main welding and tack welding is surface focusing. In vacuum electron beam welding, surface focusing means that the focus of the electron beam is precisely controlled on the workpiece surface. In tack welding, when surface focusing is performed, the energy peak is located on the workpiece surface, which is conducive to achieving ultra-shallow melting. In main welding, surface focusing can significantly reduce the temperature gradient by expanding the surface area of ​​the molten pool, achieving stable penetration depth and suppressing defects such as pores and cracks.

[0050] In some embodiments, during the cooling process in step S4, the pressure in the welding chamber during the actual welding process is increased at a rate of 0.5 Pa / min to 2 Pa / min. For example, the pressure increase rate may be 0.5 Pa / min, 1 Pa / min, 1.5 Pa / min, 2 Pa / min, or within a range of any two of the aforementioned values. This pressure increase rate results in a linear gradient of the oxygen partial pressure, which helps suppress grain boundary oxidation in the cooling phase transformation zone, uniformly releases residual stress, and thus reduces cracking.

[0051] In some embodiments, during the cooling process of step S4, gas is introduced into the welding chamber for cooling and pressurization. This cooling process can improve the uniformity of cooling, reduce the precipitation of carbides at grain boundaries, and thus reduce local hardening.

[0052] In some embodiments, the gas includes at least one of argon and helium.

[0053] In some embodiments, the cooling rate is 10°C / min-30°C / min. For example, the cooling rate can be 10°C / min, 15°C / min, 20°C / min, 25°C / min, 30°C / min, or a range between any two of the above values. Such cooling rates can effectively balance the high-temperature strength of the nickel-based alloy and the impact toughness of the niobium-tungsten alloy.

[0054] In some embodiments, the annealing treatment includes heating the cooled weldment to 1100°C-1450°C in a vacuum environment and holding the temperature for 0.5h-1h. For example, the annealing treatment may include heating the cooled weldment to 1100°C, 1200°C, 1300°C, 1400°C, 1450°C, or within a range of any two of the above values ​​in a vacuum environment, and holding the temperature for 0.5h, 0.7h, 0.8h, 0.9h, 1h, or within a range of any two of the above values. By performing the above-mentioned heating and then holding treatment on the cooled weldment, the residual brittle phase can be dissolved and the grains can be refined by recrystallization.

[0055] The welding method of the present invention is not particularly limited to the types of nickel-based alloy and niobium-tungsten alloy. In some embodiments, the niobium-tungsten alloy comprises at least one of Nb521 and Nb6621 alloys. In some embodiments, the nickel-based high-temperature alloy comprises at least one of GH4169, GH3044, and GH3625 alloys.

[0056] A second embodiment of the present invention provides a welded assembly comprising a niobium-tungsten alloy and a nickel-based alloy welded by a weld seam, wherein the welded assembly has a tensile strength of 330 MPa to 380 MPa and a hardness of 380 Hv to 480 Hv. For example, the tensile strength of the welded assembly can be 330 MPa, 340 MPa, 350 MPa, 360 MPa, 370 MPa, 380 MPa, or within a range of any two of the above values; the hardness of the welded assembly can be 380 Hv, 390 Hv, 400 Hv, 410 Hv, 420 Hv, 430 Hv, 4400 Hv, 450 Hv, 460 Hv, 470 Hv, 480 Hv, or within a range of any two of the above values. The high tensile strength and high hardness indicate that the welded assembly has both excellent load-bearing capacity and fatigue fracture resistance, achieving a high-strength metallurgical bond at the dissimilar material interface of the niobium-tungsten alloy and the nickel-based alloy. The tensile strength of the above-mentioned welded assemblies is measured in accordance with GB / T 228.1-2021, and the hardness of the welded assemblies is measured in accordance with GB / T 4340.1-2024.

[0057] In some embodiments, the welded assembly is prepared using the welding method described in any of the above embodiments.

[0058] Example

[0059] The following examples and comparative examples will further illustrate the beneficial effects of the present application, but the scope of the present invention is not limited to these examples.

[0060] Test method:

[0061] The surface roughness of the edge of the alloy plate to be welded, the tensile strength and hardness of the resulting welded assembly were tested with reference to the above method.

[0062] Example 1

[0063] 1) First, the nickel-based superalloy GH3625 and Nb521 niobium-tungsten alloy plates to be welded are machined to ensure the smoothness and straightness of the edges. The surface roughness of the edges is controlled within 0.3μm. The butt joints of the niobium alloy and the light alloy to be welded are cleaned with acetone. Then, the processed nickel-based superalloy GH3625 and Nb521 niobium-tungsten alloy plates are assembled and clamped, and the assembled plates are placed in a vacuum chamber. Then, the vacuum is evacuated to a vacuum degree of 1×10 -3Pa, the welding gap between nickel-based high-temperature alloy and Nb521 niobium-tungsten alloy plates is 0.1 mm.

[0064] 2) Perform welding in the welding room and adjust the vacuum degree of the welding room to ≤10 -3 Pa, nickel-based high-temperature alloy and Nb521 niobium-tungsten alloy plates were welded. The specific welding parameters are as follows:

[0065] Position welding adopts surface focusing, the welding length is consistent with the formal welding, the acceleration voltage is 55kV, the welding speed is 600mm / min, the electron beam is centered with the weld butt surface, the electron beam current is 28mA, and the focusing current is 638mA;

[0066] Before formal welding, adjust the electron beam flow to Nb521 offset and the beam offset is 0.25mm. The thickness of the weld joint is 3mm.

[0067] The formal welding adopts surface focusing, acceleration voltage 55kV, welding speed 600mm / min, electron beam current 50mA, and focusing current 638mA.

[0068] 3) Cool the welded plates in a vacuum chamber, fill it with filtered air, and cool it to room temperature (25°C). Anneal the welded plates at 1100°C for 0.5 hours, then cool them to room temperature to eliminate welding stress.

[0069] The final weld macromorphology is as follows: Figure 1 As shown in , it shows that the nickel-based high-temperature alloy is successfully welded with Nb521, but some spatter is generated.

[0070] Comparative Example 1

[0071] The difference from Example 1 is that the electron beam current for tack welding is 39 mA.

[0072] Comparative Example 2

[0073] The difference from Example 1 is that the electron beam in the actual welding is not offset.

[0074] Comparative Example 3

[0075] The difference from Example 1 is that the electron beam current during formal welding is 45 mA.

[0076] Comparative Example 4

[0077] The difference from Example 1 is that the annealing temperature of the weldment is 800°C.

[0078] The tensile strength and hardness of the welded assemblies of the above embodiments and comparative examples are recorded in Table 1.

[0079] Table 1

[0080] As can be seen from the data in Table 1, the tensile strength and hardness of Example 1 are both higher than those of Comparative Examples 1-4, indicating that the welded assembly obtained by the welding method of the present invention has good mechanical properties. Although some spatter is generated, it is an acceptable process-related phenomenon. The above performance data show that the above process has achieved high-strength metallurgical bonding at the interface of the dissimilar materials of niobium-tungsten alloy and nickel-based alloy.

[0081] Compared with Example 1, Comparative Example 1 uses a higher electron beam current in positioning welding, which may cause a sharp increase in local heat input, leading to rapid grain growth and reduced grain boundary strength at high temperature, which is manifested in a significant decrease in tensile strength and hardness.

[0082] Compared with Example 1 and Comparative Example 2, since the electron beam flow in the formal welding is offset by 0.25 mm towards Nb521, the heat input on the high thermal conductivity side is increased, thereby balancing the melting rates on both sides. In Comparative Example 1, after the offset is cancelled, the electron beam is centered, which may cause insufficient melting on the niobium tungsten side, causing asymmetric molten pool, resulting in increased interface shear stress, which is manifested as reduced mechanical properties of the welded assembly.

[0083] Compared with Example 1, the electron beam current of Comparative Example 3 during formal welding is lower, which directly leads to insufficient heat input during the formal welding process, which may cause incomplete fusion defects due to insufficient penetration or interface brittleness caused by insufficient diffusion, resulting in a significant reduction in the tensile strength and hardness of the welded assembly.

[0084] Compared with Comparative Example 4, Example 1 increases the annealing temperature from 800°C to 1100°C. The higher temperature may promote the dissolution of the brittle phase and the dispersion and precipitation of the strengthening phase, accelerate the mutual diffusion of elements, and thus strengthen the interface bonding, which is manifested in the increase of the tensile strength and hardness of the welded assembly.

[0085] The following examines the influence of welding process parameters on the tensile strength and hardness of welded components.

[0086] Example 2

[0087] The difference from Example 1 is that the electron beam current used in the actual welding process is 55 mA.

[0088] The final weld macromorphology is as follows: Figure 2 As shown in the figure, the weld between nickel-based high-temperature alloy and Nb521 is uniform and no spatter is generated. Figure 3 The microstructure of the weld in Example 2 is shown in FIG. 1 . It can be seen from the figure that there are no cracks or pores at the interface, and a continuous gradient transition zone is formed from Nb521 to the weld.

[0089] Example 3

[0090] The difference from Example 1 is that the accelerating voltage in the tack welding process is 60 kV, the welding speed is 1 m / min, the electron beam is centered on the weld butt surface, the electron beam current is 22 mA, and the focusing current is 635 mA. In addition, the annealing temperature in step 3) is 1200°C.

[0091] Example 4

[0092] The only difference from Example 3 is that the annealing temperature in step 3) is 1400°C.

[0093] Example 5

[0094] The only difference from Example 4 is that the annealing holding time in step 3) is 1 hour.

[0095] The tensile strength and hardness of the welded assemblies of Examples 1-5 above are reported in Table 2.

[0096] Table 2

[0097] The data of Examples 1-3 show that by properly adjusting the process conditions such as electron beam current, acceleration voltage, welding speed, and focusing current in tack welding and formal welding, higher tensile strength and hardness can be obtained, and high-quality welding of niobium tungsten alloy and nickel-based alloy can be achieved.

[0098] Comparing Example 4 with Example 1, it can be seen that further increasing the annealing temperature further strengthens the interface bonding and improves the tensile strength and hardness. Comparing Example 4 with Example 5, it can be seen that a holding time of 0.5 hours achieves higher tensile strength and hardness than 1 hour.

[0099] Although the specific embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that various modifications and substitutions may be made to those details based on all the teachings disclosed, and these changes are all within the scope of protection of the present invention. The full scope of the present invention is given by the appended claims and any equivalents thereof.

Claims

1. A method for welding a nickel-based alloy and a niobium-tungsten alloy, the method comprising the following steps: S1, assembling and clamping the nickel-based alloy and the niobium-tungsten alloy to form a component to be welded; S2, performing tack welding on the assembly to be welded using a first vacuum electron beam welding process to obtain a tack weldment, wherein the electron beam current of the tack welding is 20 mA-30 mA; S3, performing tack welding on the assembly to be welded using a second vacuum electron beam welding process to obtain a formal weldment, wherein the electron beam of the formal welding is offset toward the niobium tungsten alloy with a beam offset of 0.2 mm to 0.3 mm and an electron beam current of 50 mA to 60 mA; S4, cooling the weldment to room temperature and then annealing the weldment, wherein the annealing temperature is 1100°C-1450°C.

2. The welding method according to claim 1, wherein: The first vacuum electron beam welding process and the second vacuum electron beam welding process each independently meet any one or more of the following conditions: 1) Vacuum degree of welding chamber ≤10 -3 Pa; 2) Accelerating voltage is 50kV-60kV; 3) Welding speed is 400mm / min-600mm / min; 4) Focusing current is 630mA-640mA.

3. The welding method according to claim 1 or 2, wherein: The electron beam focusing methods for both the formal welding and the tack welding are surface focusing.

4. The welding method according to any one of claims 1 to 3, wherein: The roughness of the surfaces to be welded of the nickel-based alloy and the niobium-tungsten alloy is both ≤0.3 μm, and the gap between the surfaces to be welded of the nickel-based alloy and the niobium-tungsten alloy after being paired is 1 mm-2 mm.

5. The welding method according to any one of claims 1 to 4, wherein: During the cooling process of step S4, the pressure of the welding chamber for the formal welding is increased at a rate of 0.5 Pa / min to 2 Pa / min.

6. The welding method according to any one of claims 1 to 5, wherein: During the cooling process of step S4, gas is introduced into the welding chamber to cool and increase the pressure. Optionally, the gas includes at least one of argon and helium.

7. The welding method according to any one of claims 1 to 6, wherein: The cooling rate is 10°C / min-30°C / min.

8. The welding method according to any one of claims 1 to 7, wherein: The annealing treatment includes: -8 In a vacuum environment of 0.5 Pa, the cooled weldment is heated to 1100° C.-1450° C. and kept at this temperature for 0.5 h-1 h.

9. The welding method according to any one of claims 1 to 8, wherein: The niobium-tungsten alloy includes at least one of Nb521 and Nb6621 alloys, and / or the nickel-based high-temperature alloy includes at least one of GH4169, GH3044, and GH3625 alloys.

10. A welded assembly comprising a niobium-tungsten alloy and a nickel-based alloy welded together by a weld, wherein the welded assembly has a tensile strength of 330 MPa to 380 MPa and a hardness of 370 Hv to 480 Hv.

11. The welding assembly according to claim 10, wherein: The welded assembly is prepared by the welding method according to any one of claims 1 to 9.

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