A nickel-based flux-cored wire and a preparation method and application thereof

Abstract

The application discloses a nickel-based flux-cored wire and a preparation method and application thereof. The nano tungsten trioxide is introduced into the nickel-based flux-cored wire, the high-temperature strength and hot strength of the nickel-based alloy are improved, meanwhile, the hardness, friction performance and corrosion resistance of the alloy are improved, and the problems of low high-temperature corrosion strength, hot strength and mechanical performance of the nickel-based flux-cored wire are solved.

Description

[0001] field:

[0002] This invention relates to the field of welding materials technology, and in particular to a nickel-based flux-cored welding wire, its preparation method, and its application. Background technology:

[0003] Currently, with the rapid development of the aerospace industry, harsh environments of high temperature and corrosion have emerged, necessitating alloy materials for high-temperature components to possess superior comprehensive properties. There is an urgent need to develop new high-temperature alloys with better performance. Nickel-based superalloys possess excellent comprehensive mechanical properties, oxidation resistance, and structural stability, and are widely used in marine, petroleum, chemical, and nuclear power industries, solving engineering problems that general stainless steel and other metals and non-metals cannot address. Among them, Inconel 625 alloy exhibits excellent high-temperature creep strength, oxidation resistance, corrosion resistance, machinability, and weldability. However, under long-term service in high-temperature, high-pressure, and complex corrosive environments, it is prone to a mismatch between strength and toughness / plasticity and corrosion resistance, causing premature failure before reaching its designed service life, significantly limiting its application. Therefore, achieving high strength, good plasticity / toughness, and corrosion resistance in Inconel 625 alloy has long been a pressing issue. In recent years, adding oxide and ceramic particles to Inconel series alloys has become a popular research topic in nickel-based superalloys.

[0004] Patent CN108788516A discloses a nickel-chromium-molybdenum-tungsten nickel-based flux-cored wire, comprising a nickel-based alloy steel strip and flux powder filled within the nickel-based alloy steel strip. The flux powder has the following composition by mass percentage: 15-20% metallic chromium powder, 27-32% metallic nickel powder, 1.5-3% metallic manganese powder, 10-15% rutile, 0.5-1.5% ferrotitanium, 3-6% feldspar, 2-4% quartz, 1-2.5% rare earth fluorides, 1-3% cryolite, 4-7% ferrotungsten, 13-16% ferromolybdenum, 0.4-0.7% ferrovanadium, 1-3% calcium fluoride, and the remainder being iron powder.

[0005] Patent CN114083177B discloses a flux-cored welding wire for composite carbide-reinforced nickel-based alloy surfacing, comprising an outer metal sheath and an inner flux core. The flux core is composed of the following weight ratios: 25-40% tungsten carbide, 20-35% titanium carbide, 20-30% Ni-Cr-B-Si alloy powder, 1-3% metallic manganese, and the balance being nickel powder. Nickel serves as the binder matrix, while tungsten carbide and titanium carbide act as composite carbides, providing reinforcement and improving the wear resistance and corrosion resistance of the nickel alloy.

[0006] The addition of ferrotungsten and composite carbide ceramic particles can improve the performance of nickel-based flux-cored wires, but the additives cannot effectively change the dislocations in the material and are difficult to improve the high-temperature strength of the alloy; moreover, the additives are not evenly dispersed in the metal matrix and are prone to agglomeration, which hinders the further improvement of the performance of nickel-based flux-cored wires.

[0007] The formation of nickel-based oxide dispersion-strengthened (ODS) alloys by incorporating oxide particles has become another hot research topic in recent years. By adding inert oxide particles (such as Y₂O₃) to the alloy matrix, the uniformly dispersed oxide particles inhibit dislocation movement at high temperatures. Unlike traditional nickel-based superalloys where the γ′ phase is the main strengthening phase, nickel-based ODS alloys exhibit excellent high-temperature stability. The dissolution of the γ′ phase at high temperatures significantly reduces the mechanical properties of nickel-based superalloys. Inert nano-oxide particles possess excellent high-temperature stability, greatly improving the high-temperature mechanical properties of nickel-based ODS alloys, making them widely applicable to hot-end components of aero-engines and industrial gas turbines. In recent years, nano-oxide particles in ODS alloys have included Al₂O₃ and ThO₂, among others. Al₂O₃ particles exhibit poor high-temperature stability in the alloy, while Th in ThO₂ is a radioactive element. There is an urgent need to develop a nickel-based flux-cored welding wire with higher performance in nickel-based oxide dispersion-strengthened alloys. Summary of the Invention:

[0008] This invention provides a nickel-based flux-cored welding wire, its preparation method, and its application. By introducing nano-tungsten trioxide into the nickel-based flux-cored welding wire, the high-temperature strength and thermal strength of the nickel-based alloy are improved, while the hardness, friction properties, and corrosion resistance of the alloy are also enhanced. This solves the problems of low high-temperature corrosion resistance, thermal strength, and mechanical properties of nickel-based flux-cored welding wire.

[0009] This invention is achieved through the following technical solution:

[0010] A nickel-based flux-cored welding wire consists of an outer sheath and flux powder. The flux powder filling rate (the ratio of the flux powder mass to the sum of the flux powder and the outer sheath mass) is 30%-40%. The outer sheath is made of IN625 nickel-based alloy strip, and the inner flux powder is composed of the following components by weight percentage: Cr 21-26%, Mo 3-5%, Nb 3-5.5%, Co 0.4-1%, Zr 0.5-1%, Si 0.5-1%, Sc 0.5-1%, WO 3 0.2-1%, with the balance being Ni.

[0011] IN625 nickel-based alloy strip, by weight percentage (100%), contains the following components: C 1-2%, Cr 20.0%-23.0%, Mo 8.0%-10.0%, Al ≤0.40%, Ti ≤0.40%, Fe ≤5.00%, Nb 3.14%-4.15%, Si ≤0.50%, Mn ≤0.50%, S ≤0.015%, P ≤0.015%, Cu ≤0.070%, with Ni as the balance.

[0012] Preferably, the WO3 content in the powder is 0.5-0.8%; the WO3 purity is greater than 99%; and the WO3 particle size is 480-520 nm.

[0013] Preferably, the mass ratio of Zr, Si and Sc in the powder is 1:1:1, forming a combined deoxidizer.

[0014] Tungsten trioxide (WO3) is the most stable of the tungsten oxides, insoluble in water and inorganic acids except hydrofluoric acid, and possesses strong corrosion resistance. During heating, the crystal structure of WO3 changes, resulting in three crystal structures: monoclinic (17℃-330℃), orthorhombic (330℃-740℃), and tetragonal (≥740℃). This leads to volume changes and lattice distortion, thereby promoting sintering densification. Simultaneously, at 1000℃, WO3 can be reduced to C by C. A mixture of WO3 and C undergoes the following reaction at certain temperatures:

[0015] WO3 + 3C = 3W + 3CO (1)

[0016] 2WO3 + 3C = 2W + 3CO2 (2)

[0017] WO3 + 3CO = W + 3CO2 (3)

[0018] CO2 + C = 2CO (4)

[0019] The initial stage of the reaction is a solid-state reaction, where WO3 in close contact is reduced by carbon to produce a small amount of CO or CO2. At this stage, the reduction process is limited by the rate of C diffusion to the WO3 surface. At temperatures above 1000℃, carbon oxides can only exist in the form of CO. Therefore, with a certain concentration of CO and CO2, the reduction reaction transforms into a gas-solid reaction, thus significantly accelerating the reduction process.

[0020] Therefore, introducing nano-tungsten trioxide into nickel-based flux-cored wire can not only improve the high-temperature corrosion resistance of nickel-based alloys, but also allow the nano-tungsten trioxide to undergo a reduction reaction with the C in the alloy to generate W elements that are beneficial to the alloy, thereby improving the hardness and friction properties of the alloy, and avoiding the use of expensive tungsten powder.

[0021] The preparation method of the powder includes the following steps: uniformly dispersing nano-WO3 powder in atomized nickel powder using an electrostatic self-assembly process to obtain alloy powder; then mixing the alloy powder with a combined deoxidizer composed of Zr, Si and Sc to form core powder.

[0022] Specifically, the following steps are included:

[0023] 1) Add atomized nickel powder with a particle size of 150-200μm to a mixed solution of deionized water and n-propanol. After stirring, add 4-5wt% of 3-chloropropyltrimethoxysilane and continue stirring for 1-2 hours. Then, vacuum filter the solution to obtain atomized nickel powder with a positive surface charge.

[0024] 2) Under ice-water bath conditions, WO3 powder was added to a mixed solution of deionized water and methanol in a mass ratio of 1:1. After stirring, 4-5 wt% sodium hexadecyl sulfate was added, and stirring was continued for 1-2 hours to obtain a WO3 suspension with a negatively charged surface.

[0025] 3) Under the conditions of ice-water bath and ultrasonic stirring, the atomized nickel powder with positive surface charge obtained in step 1) is slowly added to the WO3 suspension with negative surface charge obtained in step 2). After stirring for 0.5-1h, vacuum filtration and freeze drying are performed to obtain WO3 dispersed in atomized nickel powder.

[0026] 4) Pass Zr, Si, and Sc and WO3 obtained in step 3) into the atomized nickel powder through a 60-mesh sieve, and then put the other selected powders into a V-type powder mixer and mix for 30 minutes to obtain a uniformly mixed core powder.

[0027] In step 1), the volume ratio of deionized water to n-propanol water is (1-3):5, preferably 1.5:5.

[0028] This invention also provides a method for preparing a nickel-based flux-cored welding wire, comprising the following steps: filling the flux obtained by the above-mentioned flux preparation method into an IN625 nickel-based alloy strip to obtain a nickel-based flux-cored welding wire, specifically comprising the following steps: after ultrasonic cleaning, the nickel-based alloy strip is rolled into a U-shaped groove, the flux is filled into the U-shaped groove, the U-shaped groove is closed, and then rolled and continuously drawn to reduce the diameter to prepare a welding wire; the surface of the welding wire is mechanically cleaned to obtain a flux-cored welding wire.

[0029] This invention also protects the application of the nickel-based flux-cored welding wire for surfacing welding, preferably using plasma arc welding, with the following process parameters: voltage: 20-24V; current: 100-120A; wire feed speed: 7.5m / min; gas flow rate: 18-20L / min; length of welding wire extending from the contact tip: 10-12mm.

[0030] Preferably, the nickel-based flux-cored welding wire is used for surfacing welding of the tube wall of a waste incinerator.

[0031] The beneficial effects of this invention are as follows:

[0032] (1) The introduction of nano-WO3 into nickel-based alloys improves the high-temperature strength of the alloys. The nano-WO3 particles act as pinning agents to hinder dislocation movement, thereby achieving dispersion strengthening. At high temperatures, dislocations need to consume more energy to climb over the nano-WO3 particles, and the interaction between the nano-WO3 particles and the matrix stress field has an attractive effect on dislocations, resulting in higher shear stress required for dislocations to leave the nano-WO3 particles, thus improving the high-temperature strength of the alloys.

[0033] (2) The introduction of WO3 improves the hot strength, hardness and friction properties of the alloy. The introduction of WO3 is accompanied by the presence of W. W can form a solid solution with the alloy matrix, causing lattice distortion in the matrix and hindering dislocation movement; W can enter the γ' phase, which can effectively improve the hot strength of the alloy; the introduction of W can also improve the hardness and friction properties of the alloy.

[0034] (3) The introduction of WO3 improves the corrosion resistance of the alloy. WO3 itself has strong corrosion resistance, and its introduction into nickel-based alloys can increase the corrosion resistance of the alloys to a certain extent. Moreover, during the welding process, the crystal structure of WO3 will change, producing three crystal structures: monoclinic (17℃-330℃), orthorhombic (330℃-740℃), and tetragonal (≥740℃). This leads to volume changes and lattice distortion, thereby promoting sintering densification and making the alloy more corrosion resistant.

[0035] (4) The present invention uses an electrostatic self-assembly process to uniformly disperse nano-WO3 in atomized nickel powder, which effectively avoids the agglomeration between particles, gives full play to the role of nano-WO3, and solves the problem of insufficient wettability and interfacial bonding between WO3 reinforcement and nickel matrix.

[0036] In summary, this invention introduces nano-tungsten trioxide into nickel-based flux-cored wire, improving the high-temperature strength and thermal strength of nickel-based alloys, while also enhancing the alloy's hardness, friction properties, and corrosion resistance. This solves the problems of low high-temperature corrosion resistance, thermal strength, and mechanical properties in nickel-based flux-cored wires, and avoids the use of expensive tungsten powder. Furthermore, by employing an electrostatic self-assembly process to uniformly disperse nano-WO3 in atomized nickel powder, it effectively prevents particle agglomeration, fully utilizes the role of nano-WO3, and solves the problems of insufficient wettability and interfacial bonding between the WO3 reinforcement and the nickel matrix. Attached Figure Description

[0037] Figure 1 The image shows the microstructure of the flux-cored wire with 0.5% wt nano WO3 added in Example 2 after additive manufacturing. Detailed implementation method:

[0038] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are merely for explaining the invention and are not intended to limit the invention. The parameters, proportions, etc., of the embodiments can be selected according to local conditions without substantially affecting the results.

[0039] Unless otherwise specified, all test materials used in the following examples are available through conventional commercial channels.

[0040] Example 1:

[0041] This nickel-based flux-cored welding wire consists of two parts: an outer sheath and flux powder. The outer sheath is made of IN625 nickel-based alloy steel strip with a thickness of 0.6 mm and a width of 12 mm. The flux powder composition and mass percentage are as follows (100% by total mass): Cr 22.0%, Mo 3.5%, Nb 3%, Co 0.50%, Si 0.50%, Zr 0.50%, Sc 0.50%, WO3 1%, with Ni as the balance. The flux powder filling rate is 30%, the WO3 particle size is 500 nm, and the WO3 purity is greater than 99%.

[0042] The specific steps for preparing and applying the flux-cored welding wire in this embodiment are as follows:

[0043] 1. Preparation of welding wire

[0044] (1) First, 500g of atomized nickel powder with a particle size of 200μm was added to 10L of a mixed solution of deionized water and n-propanol (volume ratio of deionized water to n-propanol was 1.5:5). After stirring for 30min, 60ml of 3-chloropropyltrimethoxysilane was added, and stirring was continued for 1h. Vacuum filtration was then performed to obtain atomized nickel powder with a positively charged surface. Under ice-water bath conditions (10℃), 7.3g of WO3 was added to 1L of a mixed solution of deionized water and methanol with a mass ratio of 1:1. After stirring for 30min, 4g of sodium hexadecyl sulfate was added, and stirring was continued for 1h to obtain a WO3 suspension with a negatively charged surface. Under ice-water bath conditions and ultrasonic stirring, the atomized nickel powder with a positively charged surface was slowly added to the WO3 suspension with a negatively charged surface. After stirring for 30min, vacuum filtration and freeze-drying were performed to obtain WO3 dispersed in atomized nickel powder.

[0045] (2) Zr, Si and Sc and WO3 dispersed in atomized nickel powder prepared in step (1) are passed through a 60-mesh sieve respectively. Then, the other selected powders are put into a V-type powder mixer and mixed for 30 minutes to obtain uniformly mixed core powder.

[0046] (3) The nickel-based alloy steel strip, after ultrasonic cleaning, is rolled and deformed on a forming machine to form a "U"-shaped groove. The flux-cored powder prepared above is added at a filling rate of 30%. After the U-shaped groove is closed, it undergoes multiple rolling, rough drawing, and fine drawing to obtain an "O"-shaped seamed flux-cored wire with a diameter of 1.2 mm. Finally, the surface of the welding wire is mechanically cleaned to obtain the final product of the flux-cored welding wire.

[0047] 2. Plasma wire welding was performed on the surface of the waste incinerator tube using a plasma arc device. The process parameters used were: voltage: 20V; current: 100A; wire feed speed: 7.5m / min; gas flow rate: 18L / min; wire extension length from the contact tip: 10mm.

[0048] Example 2

[0049] This nickel-based flux-cored welding wire consists of two parts: an outer sheath and flux powder. The outer sheath is made of IN625 nickel-based alloy steel strip with a thickness of 0.6 mm and a width of 12 mm. The flux powder composition and mass percentage are as follows (100% by total mass): Cr 23.0%, Mo 4%, Nb 4.5%, Co 0.8%, Si 0.50%, Zr 0.50%, Sc 0.50%, WO3 0.8%, with the balance being Ni. The flux powder filling rate is 30%, the WO3 particle size is 500 nm, and the WO3 purity is greater than 99%.

[0050] The specific steps of the preparation and application method of the flux-cored welding wire in this embodiment are as follows:

[0051] 1. Preparation of welding wire

[0052] (1) First, 500g of atomized nickel powder with a particle size of 200μm was added to 10L of a mixed solution of deionized water and n-propanol (volume ratio of deionized water to n-propanol was 1.5:5). After stirring for 30min, 60ml of 3-chloropropyltrimethoxysilane was added, and stirring was continued for 1h. Then, vacuum filtration was performed to obtain atomized nickel powder with a positively charged surface. Under ice-water bath conditions (10℃), 5.84g of WO3 was added to 1L of a mixed solution of deionized water and methanol with a mass ratio of 1:1. After stirring for 30min, 4g of sodium hexadecyl sulfate was added, and stirring was continued for 1h to obtain a WO3 suspension with a negatively charged surface. Under ice-water bath conditions and ultrasonic stirring, the atomized nickel powder with a positively charged surface was slowly added to the WO3 suspension with a negatively charged surface. After stirring for 30min, vacuum filtration and freeze-drying were performed to obtain WO3 dispersed in atomized nickel powder.

[0053] (2) The combined deoxidizer composed of Zr, Si and Sc and the WO3 dispersed in the atomized nickel powder prepared in step (1) are passed through a 60-mesh sieve respectively. Then, the other selected powders are put into a V-type powder mixer in proportion and mixed for 30 minutes to obtain a uniformly mixed core powder.

[0054] (3) The nickel-based alloy steel strip, after ultrasonic cleaning, is rolled and deformed on a forming machine to form a "U"-shaped groove. The flux-cored powder prepared above is added at a filling rate of 30%. After the U-shaped groove is closed, it undergoes multiple rolling, rough drawing, and fine drawing to obtain an "O"-shaped seamed flux-cored wire with a diameter of 1.2 mm. Finally, the surface of the welding wire is mechanically cleaned to obtain the final product of the flux-cored welding wire.

[0055] 2. Prepare the weld overlay layer using the flux-cored wire obtained in the process described in Example 1.

[0056] Example 3

[0057] This nickel-based flux-cored welding wire consists of two parts: an outer sheath and flux powder. The outer sheath is made of IN625 nickel-based alloy steel strip with a thickness of 0.6 mm and a width of 12 mm. The flux powder composition and mass percentage are as follows (100% by total mass): Cr 24.5%, Mo 4.5%, Nb 5%, Co 0.40%, Si 0.50%, Zr 0.50%, Sc 0.50%, WO3 0.5%, with Ni as the balance. The flux powder filling rate is 30%, the WO3 particle size is 500 nm, and the WO3 purity is greater than 99%.

[0058] The specific steps of the preparation and application method of the flux-cored welding wire in this embodiment are as follows:

[0059] 1. Preparation of welding wire

[0060] (1) First, 500g of atomized nickel powder with a particle size of 200μm was added to 10L of a mixed solution of deionized water and n-propanol (volume ratio of deionized water to n-propanol was 1.5:5). After stirring for 30min, 60ml of 3-chloropropyltrimethoxysilane was added, and stirring was continued for 1h. Then, vacuum filtration was performed to obtain atomized nickel powder with a positively charged surface. Under ice-water bath conditions (10℃), 3.65g of WO3 was added to 1L of a mixed solution of deionized water and methanol with a mass ratio of 1:1. After stirring for 30min, 4g of sodium hexadecyl sulfate was added, and stirring was continued for 1h to obtain a WO3 suspension with a negatively charged surface. Under ice-water bath conditions and ultrasonic stirring, the atomized nickel powder with a positively charged surface was slowly added to the WO3 suspension with a negatively charged surface. After stirring for 30min, vacuum filtration and freeze drying were performed to obtain WO3 dispersed in atomized nickel powder.

[0061] (2) The combined deoxidizer composed of Zr, Si and Sc and the WO3 dispersed in the atomized nickel powder prepared in step (1) are passed through a 60-mesh sieve respectively. Then, the other selected powders are put into a V-type powder mixer and mixed for 30 minutes to obtain a uniformly mixed core powder.

[0062] (3) The nickel-based alloy steel strip, after ultrasonic cleaning, is rolled and deformed on a forming machine to form a "U"-shaped groove. The flux-cored powder prepared above is added at a filling rate of 30%. After the U-shaped groove is closed, it undergoes multiple rolling, rough drawing, and fine drawing to obtain an "O"-shaped seamed flux-cored wire with a diameter of 1.2 mm. Finally, the surface of the welding wire is mechanically cleaned to obtain the final product of the flux-cored welding wire.

[0063] 2. Prepare the weld overlay layer using the flux-cored wire obtained in the process described in Example 1.

[0064] Example 4

[0065] This nickel-based flux-cored welding wire consists of two parts: an outer sheath and flux powder. The outer sheath is made of IN625 nickel-based alloy steel strip with a thickness of 0.6 mm and a width of 12 mm. The flux powder composition and mass percentage are as follows (100% by total mass): Cr 25%, Mo 5.0%, Nb 5.5%, Co 0.60%, Si 0.50%, Zr 0.50%, Sc 0.50%, WO3 0.3%, with Ni as the balance. The flux powder filling rate is 30%, the WO3 particle size is 500 nm, and the WO3 purity is greater than 99%.

[0066] The specific steps of the preparation and application method of the flux-cored welding wire in this embodiment are as follows:

[0067] 1. Preparation of welding wire

[0068] (1) First, 500g of atomized nickel powder with a particle size of 200μm was added to 10L of a mixed solution of deionized water and n-propanol (volume ratio of deionized water to n-propanol was 1.5:5). After stirring for 30min, 60ml of 3-chloropropyltrimethoxysilane was added, and stirring was continued for 1h. Then, vacuum filtration was performed to obtain atomized nickel powder with a positively charged surface. Under ice-water bath conditions (10℃), 2.19g of WO3 was added to 1L of a mixed solution of deionized water and methanol with a mass ratio of 1:1. After stirring for 30min, 4g of sodium hexadecyl sulfate was added, and stirring was continued for 1h to obtain a WO3 suspension with a negatively charged surface. Under ice-water bath conditions and ultrasonic stirring, the atomized nickel powder with a positively charged surface was slowly added to the WO3 suspension with a negatively charged surface. After stirring for 30min, vacuum filtration and freeze-drying were performed to obtain WO3 dispersed in atomized nickel powder.

[0069] (2) The combined deoxidizer composed of Zr, Si and Sc and the WO3 dispersed in the atomized nickel powder prepared in step (1) are passed through a 60-mesh sieve respectively. Then, the other selected powders are put into a V-type powder mixer and mixed for 30 minutes to obtain a uniformly mixed core powder.

[0070] (3) The nickel-based alloy steel strip, after ultrasonic cleaning, is rolled and deformed on a forming machine to form a "U"-shaped groove. The flux-cored powder prepared above is added at a filling rate of 30%. After the U-shaped groove is closed, it undergoes multiple rolling, rough drawing, and fine drawing to obtain an "O"-shaped seamed flux-cored wire with a diameter of 1.2 mm. Finally, the surface of the welding wire is mechanically cleaned to obtain the final product of the flux-cored welding wire.

[0071] 2. Prepare the weld overlay layer using the flux-cored wire obtained in the process described in Example 1.

[0072] Comparative Example 1:

[0073] Referring to Example 1, the difference is that the core powder does not contain WO3, but the other preparation processes are the same.

[0074] Based on a total mass percentage of 100%, the components and their mass percentages of the powder are as follows: Cr 22.0%, Mo 3.5%, Nb 3%, Co 0.5%, Si 0.50%, Zr 0.50%, Sc 0.50%, with Ni as the balance. The powder filling rate is 30%.

[0075] The specific steps for the preparation and application of the flux-cored welding wire in Comparative Example 1 are as follows:

[0076] (1) The combined deoxidizer composed of Zr, Si and Sc and 500g of atomized nickel powder with a particle size of 200μm were passed through a 60-mesh sieve respectively. Then, the other selected powders were put into a V-type powder mixer and mixed for 30 minutes to obtain a uniformly mixed core powder.

[0077] (2) The nickel-based alloy steel strip, after ultrasonic cleaning, is rolled and deformed on a forming machine to form a "U"-shaped groove. The flux-cored powder prepared above is then added according to the required filling rate. After the U-shaped groove is closed, it undergoes multiple rolling, rough drawing, and fine drawing processes to obtain an "O"-shaped slotted flux-cored wire with a diameter of 1.2 mm. Finally, the surface of the welding wire is mechanically cleaned to obtain the final product of the flux-cored welding wire.

[0078] (3) Prepare a weld overlay layer using the flux-cored wire obtained in the process described in Example 1.

[0079] Comparative Example 2:

[0080] Referring to Example 1, the difference is that the WO3 in the core powder is in the micron range, while the other preparation processes are the same.

[0081] Based on a total mass percentage of 100%, the components and their mass percentages of the powder are as follows: Cr 22.0%, Mo 3.5%, Nb 3%, Co 0.5%, Si 0.50%, Zr 0.50%, Sc 0.50%, with Ni as the balance. The powder filling rate is 30%.

[0082] The performance of the weld overlay samples obtained in Examples 1-4 and Comparative Examples 1-2 was tested according to GB / T39254-2020 "General Rules for Evaluation of Mechanical Properties of Additive Manufacturing Metal Parts". Friction and wear tests were conducted using a UMT-3 friction and wear testing machine at room temperature and 600℃, respectively. The test conditions were: load 10 kg, wear time 30 min, wear frequency 10 Hz, and Si3N4 balls as the grinding material. The mass of the sample and grinding balls was weighed before the wear test, and the wear loss was calculated. The results are shown in Table 1.

[0083] Table 1. Test results of friction and wear properties of the weld overlay after flux-cored welding in Examples 1-4 and Comparative Examples 1-2.

[0084]

[0085]

[0086] The performance of the weld overlay samples obtained in Examples 1-4 and Comparative Examples 1-2 was tested using high-temperature oxidation experiments. The high-temperature oxidation experiment procedure was carried out in accordance with the national standard (GB / T13303-91). The high-temperature oxidation experiment was conducted in a high-temperature muffle furnace without a protective atmosphere at a test temperature of 1000℃. The experimental procedure was as follows: the corundum crucible containing the test sample was placed in the muffle furnace and heated at a heating rate of 10℃ / min. After reaching 990℃, it was held for 10 min, and then the temperature was increased to 1000℃ at a rate of 2℃ / min. After holding for 1, 5, 10, 25, 50, 75, 100, and 150 (h) respectively, the sample was removed, cooled, weighed (total weight of crucible and sample / mass of crucible after sample removal), and the weight was recorded. Then, the sample was placed back in the muffle furnace to continue oxidation. This cycle was repeated until all oxidation cycles were completed. The weight changes during the high-temperature oxidation experiment are shown in Table 2.

[0087] Table 2. Test results of high-temperature oxidation performance of weld overlays after flux-cored welding in Examples 1-4 and Comparative Examples 1-2.

[0088] sample 1h 5h 10h 25h 50h 75h 100h 150h Example 1 0.611 0.997 1.255 1.802 3.025 4.023 5.471 7.209 Example 2 0.499 0.932 1.265 1.732 2.431 3.497 4.263 5.696 Example 3 0.499 0.932 1.265 1.732 2.431 3.497 4.263 5.696 Example 4 0.227 1.097 1.590 2.46 3.104 4.467 6.435 8.782 Comparative Example 1 0.812 2.468 4.454 9.240 13.996 17.878 20.979 25.494 Comparative Example 2 0.430 0.857 1.399 1.973 2.547 4.464 6.463 8.078

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nickel-based flux-cored welding wire, characterized in that, The product consists of two parts: an outer sheath and a core powder. The core powder filling rate is 30%-40%. The outer sheath is an IN625 nickel-based alloy strip, and the core powder, by weight percentage (100%), comprises the following components: Cr 21-26%, Mo 3-5%, Nb 3-5.5%, Co 0.4-1%, Zr 0.5-1%, Si 0.5-1%, Sc 0.5-1%, WO3 0.5-0.8%, with the balance being Ni. The preparation method of the core powder includes the following steps: uniformly dispersing nano-WO3 powder in atomized nickel powder using an electrostatic self-assembly process to obtain alloy powder; then mixing the alloy powder with a combined deoxidizer composed of Zr, Si, and Sc to form a core powder; the purity of WO3 in the core powder is greater than 99%; the particle size of WO3 is 480-520 nm; the IN625 nickel-based alloy strip, by weight percentage (100%), contains the following components: C 1~2%, Cr 20.0%~23.0%, Mo 8.0%~10.0%, Al≤0.40%, Ti≤0.40%, Fe≤5.00%, Nb 3.14%~4.15%, Si≤0.50%, Mn≤0.50%, S≤0.015%, P≤0.015%, Cu≤0.070%, Ni is the balance.

2. The nickel-based flux-cored welding wire according to claim 1, characterized in that, The mass ratio of Zr, Si and Sc in the powder is 1:1:

1.

3. The nickel-based flux-cored welding wire according to claim 1, characterized in that, The preparation method of the medicinal powder specifically includes the following steps: 1) Add atomized nickel powder with a particle size of 150-200 μm to a mixed solution of deionized water and n-propanol, stir, add 4-5 wt% of 3-chloropropyltrimethoxysilane, continue stirring for 1-2 h, and then vacuum filter to obtain atomized nickel powder with a positive surface charge. 2) Under ice-water bath conditions, WO3 powder was added to a mixed solution of deionized water and methanol in a mass ratio of 1:

1. After stirring, 4-5 wt% sodium hexadecyl sulfate was added, and stirring was continued for 1-2 h to obtain a WO3 suspension with a negative surface charge. 3) Under the conditions of ice-water bath and ultrasonic stirring, the atomized nickel powder with positive surface charge obtained in step 1) is slowly added to the WO3 suspension with negative surface charge obtained in step 2). After stirring for 0.5-1 h, vacuum filtration and freeze drying are performed to obtain WO3 dispersed in atomized nickel powder. 4) Pass Zr, Si, and Sc and WO3 obtained in step 3) into the atomized nickel powder through a 60-mesh sieve, and then put the other selected powders into a V-type powder mixer and mix for 30 minutes to obtain a uniformly mixed core powder.

4. The nickel-based flux-cored welding wire according to claim 3, characterized in that, In step 1), the volume ratio of deionized water to n-propanol water is (1-3):

5.

5. The application of the nickel-based flux-cored welding wire according to claim 1, characterized in that, For surfacing welding, plasma arc welding is used. The process parameters are: voltage: 20-24 V; current: 100-120 A; wire feed speed: 7.5 m / min; gas flow rate: 18-20 L / min; wire extension length from the contact tip: 10-12 mm.

6. The application according to claim 5, characterized in that, It is used for surfacing welding on the tube walls of waste incinerators.

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