Corrosion-resistant nickel-based alloy welding wire and production process thereof

Abstract

The invention belongs to the technical field of nickel-based alloy welding wires, and discloses a corrosion-resistant nickel-based alloy welding wire and a production process thereof, and the corrosion-resistant nickel-based alloy welding wire comprises the following components in percentage by mass: 50-65% of nickel, 16-24% of chromium, 8-10% of molybdenum, 3.5-5.5% of niobium and tantalum, 3-4.5% of copper, 3-4% of tungsten, 0.5-1.0% of tin, 0.1-0.3% of rare earth element, 0.1-0.5% of grain boundary optimizer, 2-5% of nano reinforced phase and the balance of Fe and other inevitable impurities. Through multi-element alloying design, nano reinforced phase compounding and gradient coating synergistic effect, comprehensive improvement of corrosion resistance, high-temperature mechanical property and welding manufacturability is achieved; a welding wire base body is based on nickel, a compact and self-repairing gradient oxidation film is formed by accurately regulating and controlling the atomic proportion of chromium, molybdenum and tungsten, and the chloride ion permeation resistance and the high-temperature oxidation resistance are remarkably improved; therefore, the welding wire has excellent corrosion resistance, high-temperature strength and welding adaptability.

Description

Technical Field

[0001] The present invention relates to the technical field of nickel-based alloy welding wires, and particularly relates to a corrosion-resistant nickel-based alloy welding wire and its production process. Background Technique

[0002] As a core product in the field of welding materials, the technical development of nickel-based alloy welding wires is deeply rooted in the unique properties of nickel-based alloys and the in-depth integration of industrial needs. Nickel-based alloys are based on nickel and form a solid solution strengthening system by adding elements such as chromium, molybdenum, tungsten, and cobalt. They have excellent high-temperature oxidation resistance, resistance to local corrosion (such as pitting corrosion and crevice corrosion), and high-temperature strength stability. Especially in extreme environments containing corrosion media such as Cl - , H2S, sulfuric acid, etc., they show performance advantages that traditional stainless steels cannot replace. With the increasingly harsh service conditions of equipment in fields such as aerospace, nuclear power, ocean engineering, and petrochemical industries, the application scenarios of nickel-based alloy welding wires have expanded from conventional corrosion-resistant environments to key fields such as high-temperature and high-pressure gas turbine components, internal components of nuclear reactors, and deep-sea oil and gas pipelines, becoming the core materials to ensure the long-term safe operation of equipment.

[0003] Nickel-based alloy welding wires have evolved from single-component to multi-component composites. Early nickel-copper alloys (such as Monel400) had basic corrosion resistance, but were prone to stress corrosion cracking in high-temperature chloride or molten salt environments. Subsequently developed nickel-chromium-molybdenum alloys (such as Inconel 625, Hastelloy C-276) significantly improved the self-repair ability of the passivation film and the intergranular corrosion resistance by optimizing the Cr / (Mo+W) atomic ratio (2.5-3.5) and adding grain boundary stabilizing elements such as niobium and titanium.

[0004] However, the existing technologies still have significant defects: First, in high-temperature (>800°C) and strongly oxidizing acidic environments (such as concentrated sulfuric acid), the corrosion rate of traditional welding wires increases rapidly due to insufficient stability of the oxide film; second, during the welding process, the fluidity of the molten pool is poor and the penetration is shallow, which easily leads to defects such as lack of fusion and an increase in the sensitivity to hot cracks; third, the segregation of impurity elements (sulfur, phosphorus) and the precipitation of grain boundary carbides result in the mismatch of the mechanical properties (such as tensile strength and impact toughness) of the weld and the base metal. In addition, the increasingly strict environmental protection situation puts forward low-carbon requirements for the production process of welding wires, and the high-energy-consuming melting and coating processes in the existing technologies are difficult to meet the green manufacturing standards.

[0005] The current technical bottleneck focuses on the collaborative optimization of composition-process-performance. Although the introduction of nano-reinforced phases (such as boron nitride, CeB6) can improve the fluidity of the molten pool and inhibit crack propagation, their dispersion uniformity and interfacial bonding strength are still restricted by the ball milling process parameters. Gradient coating technologies (such as Ni-Cr-Mo / TiC double-layer structure) can delay Cl -It can penetrate, but the difference in the thermal expansion coefficients of the coating and the substrate at high temperatures easily causes spalling.

[0006] Therefore, how to provide a corrosion-resistant nickel-based alloy welding wire and its production process is an urgent problem to be solved at present. Summary of the Invention

[0007] Embodiments of the present invention provide a corrosion-resistant nickel-based alloy welding wire and its production process to solve the above technical problems existing in the prior art.

[0008] To have a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary part is not a general review, nor is it to identify key / important constituent elements or delineate the protection scope of these embodiments. Its sole purpose is to present some concepts in a simple form as a preface to the subsequent detailed description.

[0009] According to the first aspect of the embodiments of the present invention, a corrosion-resistant nickel-based alloy welding wire is provided.

[0010] In one embodiment, the corrosion-resistant nickel-based alloy welding wire comprises the following components by mass percentage: Nickel: 50 - 65%, Chromium: 16 - 24%, Molybdenum: 8 - 10%, Niobium + Tantalum: 3.5 - 5.5%, Copper: 3 - 4.5%, Tungsten: 3 - 4%, Tin: 0.5 - 1.0%, Rare earth elements: 0.1 - 0.3%, Grain boundary optimizer: 0.1 - 0.5%, Nano-reinforcing phase: 2 - 5%, and the balance is Fe and other inevitable impurities.

[0011] In one embodiment, the rare earth elements are a mixture of cerium and lanthanum, and the mass ratio of cerium to lanthanum is 1:1.

[0012] In one embodiment, the mass ratio of tin to copper is 1:3 - 1:5, which is used to inhibit high-temperature fusion welding cracks.

[0013] In one embodiment, the nano-reinforcing phase includes at least one of boron nitride nanosheets, cerium hexaboride, titanium carbide, vanadium carbide, or nickel-coated cerium oxide nanocapsules, and the particle size of the nano-reinforcing phase is 20 - 50 nm.

[0014] In one embodiment, the grain boundary optimizer includes at least one of zirconium and tellurium, which is used to inhibit intergranular corrosion and carbide segregation.

[0015] In one embodiment, the atomic percentages of chromium, molybdenum, and tungsten satisfy Cr / (Mo + W) = 2.5 - 3.5.

[0016] In one embodiment, the tensile strength of the welding wire is ≥680 MPa, the high-temperature creep strength at 750 °C is ≥240 MPa, and the corrosion rate in a molten salt environment is ≤0.08 mm / y.

[0017] In one embodiment, the impurity control is as follows: sulfur ≤0.005%, phosphorus ≤0.008%, and when the iron content is ≤7%, the mass ratio of sulfur to phosphorus is ≤0.6.

[0018] In one embodiment, the surface of the welding wire is coated with a gradient coating, which includes an inner layer and an outer layer. The inner layer is a nano Ni-Cr-Mo alloy layer with a thickness of 0.5 - 1.5 μm, and the outer layer is a nano Ni-Cr-Mo alloy layer with a thickness of 0.2 - 0.5 μm.

[0019] According to the second aspect of the embodiments of the present invention, a production process of a corrosion-resistant nickel-based alloy welding wire is provided.

[0020] In one embodiment, the production process of the corrosion-resistant nickel-based alloy welding wire includes: Select raw materials according to a preset composition ratio, and prepare nano-reinforcing phase materials through high-energy ball milling; Vacuum induction melting is carried out on the weighed raw materials. Under the condition of a vacuum degree ≤1×10 -2 Pa, nickel, chromium, molybdenum, tungsten, and iron-based materials are added in sequence. The melting temperature is raised to 1550 - 1600 °C and held for 30 minutes for deoxidation. The melt is homogenized by electromagnetic stirring. Then, niobium, tantalum, copper, tin, and rare earth elements are added. After the melt is fully mixed, it is poured into a water-cooled copper mold to form an ingot; The ingot is used as a consumable electrode for electroslag remelting. Using a CaF2-CaO-Al2O3 slag system, after homogenization annealing at 1200 - 1250 °C for 24 hours, it is heated to 1180 - 1200 °C for multi-directional forging; The billet is processed into a Φ8 mm wire rod through multi-pass hot rolling. After the wire rod is pickled to remove the oxide scale, cold drawing and intermediate annealing are carried out to eliminate work hardening, and then it is precision drawn in multiple passes to the target diameter; The nano-reinforcing phase and alloy powder are mixed through a ball milling and dispersion process, and a gradient coating is deposited on the surface of the welding wire step by step using arc ion plating and magnetron sputtering technologies; Boundary optimization is achieved through vacuum annealing. In an 850 °C environment, a H2 / Ar mixed gas is introduced and held for 2 hours to promote the segregation of the grain boundary optimizer at the grain boundary, forming ZrO2 nanoparticles and Te-Cu eutectic phases. Finally, solution strengthening and vacuum annealing at 550 °C for 30 minutes are carried out to eliminate residual stress, and a finished nickel-based alloy welding wire is obtained.

[0021] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: 1. Through the combined effects of multi-element alloying design, nano-reinforcement phase composite, and gradient coating, the comprehensive improvement of corrosion resistance, high-temperature mechanical properties, and welding processability is achieved. The wire matrix is nickel-based. By precisely controlling the atomic ratios of chromium, molybdenum, and tungsten, a dense and self-healing gradient oxide film is formed, significantly enhancing the resistance to chloride ion penetration and high-temperature oxidation. Adding niobium, tantalum composite carbides, and rare earth elements optimizes the grain boundary structure, inhibits intergranular corrosion and carbide segregation. The nano-reinforcement phase improves the fluidity of the molten pool to reduce the spatter rate and simultaneously enhances the creep resistance. The surface gradient coating further blocks the diffusion path of corrosive media, ensuring long-term service stability in extreme environments, so that the wire has excellent corrosion resistance, high-temperature strength, and welding adaptability.

[0022] 2. Through the dual optimization of passivation film-forming elements and grain boundary engineering, a breakthrough improvement in corrosion resistance is achieved. Chromium, molybdenum, and tungsten form a gradient oxide film at a specific atomic ratio: the outer layer of molybdenum- and tungsten-rich oxides (MoO3, W2O5) preferentially consumes Cl - ions, delaying the penetration of corrosive media; the inner layer of chromium-rich oxide (Cr2O3) provides a continuous and dense protective layer, and the breakdown potential of the passivation film ≥ 1.2 V (vs. SCE). The synergistic effect of rare earth elements (Ce / La) and zirconium purifies the grain boundaries, adsorbs sulfur and phosphorus impurities, and forms CeCrO3 composite oxides, reducing the intergranular corrosion rate to less than 40% of that of traditional wires. Nickel-coated cerium oxide (Ni@CeO2) nanocapsules release active Ce 3+ in a high-temperature corrosion environment, dynamically repairing the defects of the oxide film and significantly extending the life of the passivation film. In addition, the surface TiC ceramic layer remains chemically inert in a molten salt environment, inhibiting the initiation of local pitting corrosion.

[0023] 3. Through the multi-scale synergy of solid solution strengthening, dispersion strengthening, and grain boundary optimization, the simultaneous improvement of high-temperature mechanical properties and welding process stability is achieved. The high-entropy alloying of cobalt and manganese in the matrix forms a Ni-Co-Mn solid solution, enhancing the high-temperature phase stability; niobium, tantalum composite carbides (NbC / TaC) and nano-reinforcement phases (VC, BN) as dispersion strengthening phases inhibit dislocation slip and grain boundary migration, increasing the high-temperature creep rupture strength at 750 °C to ≥ 240 MPa (1000 h). Grain boundary optimizers (Zr, Te) refine the grains to 5 - 8 μm, inhibiting the tendency of high-temperature ductility-dip cracking (DDC), and the impact toughness (20 °C) ≥ 120 J / cm 2 . In the welding process, boron nitride nanosheets (BN) reduce the spatter rate to ≤ 5% and the wetting angle to ≤ 15° by reducing the viscosity of the molten pool, suitable for all-position automatic welding; the gradient coating maintains a low porosity (≤ 15%) at high temperatures, avoiding coating spalling caused by thermal cycling.

[0024] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present invention. Description of the Drawings

[0025] The drawings herein are incorporated into and constitute a part of this specification, showing embodiments in accordance with the present invention, and are used together with the specification to explain the principles of the present invention.

[0026] Figure 1 It is a flowchart of a production process of a corrosion-resistant nickel-based alloy welding wire shown according to an exemplary embodiment. Detailed Embodiments

[0027] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0028] In a first aspect, an embodiment of a corrosion-resistant nickel-based alloy welding wire of the present invention is provided.

[0029] In this alternative embodiment, the corrosion-resistant nickel-based alloy welding wire comprises the following components by mass percentage: Nickel (Ni): 50 - 65%, Chromium (Cr): 16 - 24%, Molybdenum (Mo): 8 - 10%, Niobium (Nb) + Tantalum (Ta): 3.5 - 5.5%, Copper (Cu): 3 - 4.5%, Tungsten (W): 3 - 4%, Tin (Sn): 0.5 - 1.0%, Rare earth elements: 0.1 - 0.3%, Grain boundary optimizer: 0.1 - 0.5%, Nano-reinforcing phase: 2 - 5%, and the balance is Fe and other inevitable impurities.

[0030] In this alternative embodiment, the rare earth elements are a mixture of cerium (Ce) and lanthanum (La), and the mass ratio of cerium (Ce) to lanthanum (La) is 1:1.

[0031] In this alternative embodiment, the mass ratio of tin (Sn) to copper (Cu) is 1:3 - 1:5, which is used to inhibit high-temperature fusion welding cracks.

[0032] In this alternative embodiment, the nano-reinforcing phase includes at least one of boron nitride nanosheets (BN), cerium hexaboride (CeB6), titanium carbide (TiC), vanadium carbide (VC), or nickel-coated cerium oxide (Ni@CeO2) nanocapsules, and the particle size of the nano-reinforcing phase is 20 - 50 nm.

[0033] In this alternative embodiment, the grain boundary optimizer includes at least one of zirconium (Zr) and tellurium (Te), which is used to inhibit intergranular corrosion and carbide segregation.

[0034] In this alternative embodiment, the atomic percentages of chromium (Cr), molybdenum (Mo), and tungsten (W) satisfy Cr / (Mo + W) = 2.5 - 3.5.

[0035] In this alternative embodiment, the tensile strength of the welding wire is ≥680 MPa, the high-temperature creep strength at 750 °C is ≥240 MPa (1000 h), and the corrosion rate in a molten salt (NaCl-KCl) environment is ≤0.08 mm / y.

[0036] In this alternative embodiment, the impurity control is as follows: sulfur (S) ≤0.005%, phosphorus (P) ≤0.008%, and when the Fe content is ≤7%, the S / P mass ratio is ≤0.6.

[0037] In this alternative embodiment, the surface of the welding wire is coated with a gradient coating, which includes an inner layer and an outer layer. The inner layer is a nano Ni-Cr-Mo alloy layer with a thickness of 0.5 - 1.5 μm, and the outer layer is a nano Ni-Cr-Mo alloy layer with a thickness of 0.2 - 0.5 μm.

[0038] In the second aspect, Figure 1 An embodiment of a production process of a corrosion-resistant nickel-based alloy welding wire of the present invention is shown.

[0039] In this alternative embodiment, the production process of the corrosion-resistant nickel-based alloy welding wire includes: S101. Select raw materials according to a preset composition ratio and prepare nano-reinforcing phase materials by high-energy ball milling.

[0040] S102. Vacuum induction melt the weighed raw materials. Under the condition of a vacuum degree ≤1×10 -2 Pa, successively add nickel, chromium, molybdenum, tungsten, and iron-based materials. Raise the melting temperature to 1550 - 1600 °C and hold for 30 minutes for deoxidation. Make the melt homogeneous by electromagnetic stirring. Then add niobium, tantalum, copper, tin, and rare earth elements. After the melt is fully mixed, pour it into a water-cooled copper mold to form an ingot.

[0041] S103. Use the ingot as a consumable electrode for electroslag remelting. Adopt a CaF2-CaO-Al2O3 slag system. After homogenization annealing at 1200 - 1250 °C for 24 hours, heat it to 1180 - 1200 °C for multi-directional forging; S104. Process the billet into a Φ8 mm wire rod through multi-pass hot rolling. After pickling the wire rod to remove the oxide scale, perform cold drawing and intermediate annealing to eliminate work hardening, and then perform multi-pass precision drawing to the target diameter.

[0042] S105. Mix the nano-reinforcing phase and alloy powder through a ball milling and dispersion process, and use arc ion plating and magnetron sputtering technologies to deposit a gradient coating on the surface of the welding wire step by step.

[0043] S106. Achieve grain boundary optimization through vacuum annealing. Introduce a mixed gas of H2 / Ar into the environment at 850°C and keep it warm for 2 hours to promote the segregation of the grain boundary optimizer at the grain boundaries, forming ZrO2 nanoparticles and Te-Cu eutectic phase. Finally, perform solution strengthening and vacuum annealing at 550°C for 30 minutes to eliminate residual stress, obtaining the finished nickel-based alloy welding wire.

[0044] The following combines specific embodiments to explain the present invention in detail.

[0045] Example 1 1. The corrosion-resistant nickel-based alloy welding wire includes the following components by mass percentage: Nickel (Ni) 58 g, Chromium (Cr) 18.8 g, Molybdenum (Mo) 9 g, Niobium + Tantalum (Nb + Ta) 3.5 g, Copper (Cu) 3 g, Tungsten (W) 3.5 g, Tin (Sn) 0.5 g, Rare earth elements (Ce / La = 1:1) 0.2 g, Zirconium (Zr) 0.3 g, Nano-reinforcing phase (BN + Ni@CeO2) 2.2 g, Fe balance 1 g.

[0046] 2. Preparation process (simple): Vacuum induction melting (vacuum degree ≤ 1×10 -2 Pa, temperature 1580°C, keep warm for 30 min), electroslag remelting (slag system CaF2-CaO-Al2O3, current density 1.0 A / mm 2 ), homogenization annealing (1230°C, 24 h); Hot roll to Φ8 mm wire rod, cold draw to Φ1.6 mm, surface gradient coating (inner Ni-Cr-Mo alloy layer 1.0 μm, outer TiC ceramic layer 0.3 μm).

[0047] 3. Performance test: 3.1 Tensile strength: 705 MPa (room temperature), high-temperature creep strength (750°C / 1000 h): 255 MPa; 3.2 Corrosion rate (NaCl-KCl molten salt, 90 days): 0.07 mm / y; 3.3 Intergranular corrosion (ASTM G28): no cracks, and ZrO2 nanoparticles are dispersed at the grain boundaries.

[0048] Example 2 1. The corrosion-resistant nickel-based alloy welding wire includes the following components by mass percentage: Nickel (Ni) 52 g, Chromium (Cr) 22 g, Molybdenum (Mo) 10 g, Niobium + Tantalum (Nb + Ta) 3.5 g, Copper (Cu) 3 g, Tungsten (W) 4 g, Rare earth elements (Ce / La = 1:1) 0.3 g, Tellurium (Te) 0.5 g, Nano-reinforcing phase (VC + CeB6) 4 g, Fe balance 0.7 g.

[0049] 2. Process Optimization: After electroslag remelting, vacuum consumable refining is added (the impurity S / P contents are ≤0.004% / 0.006% respectively); The outer layer of the gradient coating is changed to a CeB6-doped Ni-Cr-Mo layer (0.5 μm) to improve high-temperature oxidation resistance.

[0050] 3. Performance Data: 3.1 Tensile strength: 690 MPa, elongation: 38%; 3.2 High-temperature creep rate (750°C / 200 MPa): 1.2×10 -8 / s; 3.3 Molten salt corrosion rate: 0.05 mm / y (superior to Example 1 because Te-Cu eutectic inhibits grain boundary segregation).

[0051] Example 3 1. Composition Design: Nickel (Ni) 61 g, chromium (Cr) 16 g, molybdenum (Mo) 9.5 g, niobium + tantalum (Nb+Ta) 3.5 g, copper (Cu) 4.0 g, tungsten (W) 3 g, rare earth elements (Ce / La = 1:1) 0.3 g, zirconium (Zr) 0.2 g, nano-reinforcing phase (TiC + BN) 2 g, Fe balance 0.5 g.

[0052] 2. Process Features: After cold drawing, hydrogen annealing treatment (1050°C, H2 / Ar mixed gas) is added to refine the grains to 8 μm; The surface coating adopts a magnetron sputtering-deposited Ni-Cr-Mo-CeO2 composite layer (thickness 1.2 μm).

[0053] 3. Performance Verification: 3.1 Tensile strength: 680 MPa, impact toughness (-50°C): 85 J; 3.2 High-temperature oxidation weight gain (800°C / 500 h): 1.3 mg / cm 2 (Traditional welding wire ≥ 3.5 mg / cm 2 ) 3.3 Sulfur-phosphorus ratio control (S / P = 0.55): No sulfide segregation at grain boundaries.

[0054] Comparative Example 1 (without nano-reinforcing phase + conventional coating) 1. Composition Adjustment: Remove the nano-reinforcing phase, and the grain boundary optimizer only contains 0.2 g of Zr. The coating is a single Ni-Cr layer (1.0 μm).

[0055] 2. Performance Comparison: 2.1, Tensile strength: 620MPa (decreased by 12%), high temperature endurance strength: 180MPa (decreased by 30%); 2.2, Corrosion rate: 0.15mm / y (significant degradation); 2.3. Microscopic defects: SEM shows that carbides are segregated at grain boundaries and the loss of nanophase leads to crack propagation.

[0056] Comparative Example 2 (Existing Technology: Inconel 625 Welding Wire) 1. Composition reference: Ni ≥ 58g, Cr 20-23g, Mo 8-10g, Nb 3.15-4.15g, Fe ≤ 5g (without rare earth, grain boundary optimizer and gradient coating).

[0057] 2. Performance differences: 2.1. Tensile strength: 650 MPa, 750°C endurance strength: 200 MPa (25% lower than Example 1); 2.2. Molten salt corrosion rate: 0.12 mm / y (71% higher than Example 1); 2.3. Intergranular corrosion susceptibility: Microcracks appear in the ASTM G28 test (due to the lack of Ce / La to purify the grain boundaries).

[0058] The performance comparison analysis of Examples 1, 2, and 3 and Comparative Examples 1 and 2 is shown in Tables 1 and 2.

[0059] Table 1: Comparison of ingredients and process parameters

[0060] Table 2: Comparison of mechanical and corrosion properties

[0061] Through the coordinated design of optimized composition (e.g., Cr / (Mo+W) = 2.5-3.5), nano-reinforcement phases (e.g., BN, CeB6), and gradient coatings (Ni-Cr-Mo / TiC), this welding wire significantly outperforms conventional technologies (e.g., Inconel 625) in tensile strength (≥680MPa), corrosion resistance (molten salt corrosion rate ≤0.08mm / y), and yield (≥96%). Comparative examples demonstrate the necessity of nano-reinforcement phases and grain boundary optimization, as existing technologies, due to their limited composition and process, struggle to meet the demands of extreme operating conditions.

[0062] The present invention is not limited to the structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A corrosion-resistant nickel-based alloy welding wire, characterized in that, Comprising components in the following mass percentages: Nickel: 50 - 65%, Chromium: 16 - 24%, Molybdenum: 8 - 10%, Niobium + Tantalum: 3.5 - 5.5%, Copper: 3 - 4.5%, Tungsten: 3 - 4%, Tin: 0.5 - 1.0%, Rare earth elements: 0.1 - 0.3%, Grain boundary optimizer: 0.1 - 0.5%, Nano-reinforcing phase: 2 - 5%, the balance being Fe and other inevitable impurities.

2. The corrosion-resistant nickel-based alloy welding wire according to claim 1, characterized in that, The rare earth elements are a mixture of cerium and lanthanum, and the mass fraction ratio of cerium to lanthanum is 1:

1.

3. The corrosion-resistant nickel-based alloy welding wire according to claim 1, wherein, The mass ratio of tin to copper is 1:3 - 1:5, which is used to inhibit high-temperature fusion welding cracks.

4. The corrosion-resistant nickel-based alloy welding wire according to claim 1, characterized in that, The nano-reinforcing phase includes at least one of boron nitride nanosheets, cerium hexaboride, titanium carbide, vanadium carbide or nickel-coated cerium oxide nanocapsules, and the particle size of the nano-reinforcing phase is 20 - 50 nm.

5. The corrosion-resistant nickel-based alloy welding wire according to claim 1, wherein The grain boundary optimizer includes at least one of zirconium and tellurium, which is used to inhibit intergranular corrosion and carbide segregation.

6. The corrosion-resistant nickel-based alloy welding wire according to claim 1, characterized in that The atomic percentages of chromium, molybdenum and tungsten satisfy Cr / (Mo + W) = 2.5 - 3.

5.

7. The corrosion-resistant nickel-based alloy welding wire according to claim 1, characterized in that, The tensile strength of the welding wire ≥ 680 MPa, the high-temperature creep strength at 750 °C ≥ 240 MPa, and the corrosion rate in a molten salt environment ≤ 0.08 mm / y.

8. The corrosion-resistant nickel-based alloy welding wire according to claim 1, wherein The impurities are controlled as follows: sulfur ≤ 0.005%, phosphorus ≤ 0.008%, and when the iron content ≤ 7%, the mass ratio of sulfur to phosphorus ≤ 0.

6.

9. The corrosion-resistant nickel-based alloy welding wire according to claim 1, characterized in that, The surface of the welding wire is coated with a gradient coating. The gradient coating includes an inner layer and an outer layer. The inner layer is a nano Ni-Cr-Mo alloy layer with a thickness of 0.5 - 1.5 μm, and the outer layer is a nano Ni-Cr-Mo alloy layer with a thickness of 0.2 - 0.5 μm.

10. A production process of a corrosion-resistant nickel-based alloy welding wire, which is used to produce the corrosion-resistant nickel-based alloy welding wire described in any one of claims 1-9, and is characterized in that, Including: Select raw materials according to a preset composition ratio, and prepare nano-reinforcing phase materials by high-energy ball milling; The weighed raw materials are subjected to vacuum induction melting. Under the condition of a vacuum degree ≤ 1×10 -2 Pa, nickel, chromium, molybdenum, tungsten and iron-based materials are sequentially added. The melting temperature is raised to 1550 - 1600 °C and held for 30 minutes for deoxidation. The melt is homogenized by electromagnetic stirring. Then niobium, tantalum, copper, tin and rare earth elements are added. After the melt is fully mixed, it is poured into a water-cooled copper mold to form an ingot; Use the ingot as a consumable electrode for electroslag remelting, adopt a CaF2-CaO-Al2O3 slag system, after homogenization annealing at 1200 - 1250 °C for 24 hours, heat to 1180 - 1200 °C for multi-directional forging; Process the billet into a Φ8 mm wire rod through multi-pass hot rolling. After pickling the wire rod to remove the oxide scale, perform cold drawing and intermediate annealing to eliminate work hardening, and then perform multi-pass precision drawing to the target diameter; Mix the nano-reinforcing phase and alloy powder through a ball milling dispersion process, and deposit them on the surface gradient coating of the welding wire step by step using arc ion plating and magnetron sputtering technologies; Achieve grain boundary optimization through vacuum annealing. Introduce a H2 / Ar mixed gas in an 850 °C environment and hold for 2 hours to promote the segregation of the grain boundary optimizer at the grain boundary, form ZrO2 nanoparticles and Te-Cu eutectic phases, and finally perform solution strengthening and vacuum annealing at 550 °C for 30 minutes to eliminate residual stress, obtaining the finished nickel-based alloy welding wire.

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