Metal flux-cored welding wire for wind turbines, its preparation method and application method

Abstract

This invention discloses a metal flux-cored welding wire for wind turbines, comprising flux powder and a welding sheath. The flux powder is composed of the following components: Ni: 58%-80%, Cr: 10%-16%, Mo: 4%-12%, Nb: 1%-3%, Fe: 2%-14%, C: 0.1%-0.2%, Mn: 0.2%-0.5%, Si: 0.2%-0.5%, with the sum of the mass percentages of the above components being 100%. The welding sheath is made of Inconel 718 alloy strip. This invention also discloses a method for preparing and applying the metal flux-cored welding wire for wind turbines. This invention solves the problem of pitting corrosion and abrasive wear on the surface of high-speed gears in existing wind turbines, particularly in environments with high corrosion resistance requirements, such as offshore and desert environments with high wear resistance requirements, resulting in corrosion pits and wear microcracks.

Description

Technical Field

[0001] This invention belongs to the field of surface engineering technology for strengthening medium carbon steel 40CrNiMoA material, specifically relating to metal flux-cored welding wire for wind turbines. This invention also relates to the preparation method and application method of metal flux-cored welding wire for wind turbines. Background Technology

[0002] Gears are the core mechanical components of the transmission system in wind turbine generators, and the performance of high-speed gears has a decisive impact on the overall operational stability of the machine. However, due to the long-term exposure to complex alternating loads, key components such as gears are prone to wear and fatigue failures, leading to high downtime maintenance costs. The high-speed gearbox operates through multi-stage gear transmission, providing high rotational speeds to the generator and converting the wind energy captured by the rotor into mechanical power, which is then transmitted to the generator. Since the rotor's rotational speed is very low (typically only a dozen revolutions per minute), while the generator requires very high speeds (usually thousands of revolutions per minute) to generate electricity normally, high speeds demand excellent wear resistance from the gear materials. However, wind turbines typically operate in harsh environments, causing rapid wear on the gear surfaces and shortening their lifespan. Gears are generally required to have a service life of 20 years, but without regular surface treatment, they may only last 7 years. Replacing gears is extremely costly and difficult.

[0003] To address this challenge, cladding nickel-based alloys onto the surface of wind turbines can improve the material's surface hardness, wear resistance, and corrosion resistance, effectively solving the aforementioned difficulties. Surface treatment processes such as cladding and welding can effectively improve the surface properties of gear materials, thereby extending their service life and reducing maintenance costs.

[0004] Nickel-based alloys are widely used in aerospace and high-end equipment manufacturing due to their excellent corrosion resistance, high temperature resistance, and oxidation resistance. In the power generation field, nickel-based alloys are used in equipment such as gas turbines and nuclear reactor pressure vessels, and the matching welding materials typically require corrosion resistance, high strength, and high hardness. The composition range of the alloy powder elements and the content of impurities such as sulfur and phosphorus in nickel-based alloy flux-cored welding wire are strictly controlled. Medium-carbon alloy steel 40CrNiMoA is commonly used for high-speed gears in wind turbines, suitable for use in normal environmental conditions. However, in offshore wind turbines with high corrosion resistance requirements and in desert environments with high wear resistance requirements, pitting corrosion and abrasive wear can occur on the surface of the high-speed gears, resulting in corrosion pits and wear microcracks. These problems shorten the service life of wind turbine gears and increase safety hazards. Furthermore, due to its high carbon equivalent, it is prone to cold cracking during welding. Summary of the Invention

[0005] The purpose of this invention is to provide a metal flux-cored welding wire for wind turbines, which solves the problem that the medium carbon alloy steel 40CrNiMoA, which is usually used as the material for high-speed gears in existing wind turbines, causes pitting corrosion and abrasive wear on the surface of high-speed gears in offshore wind turbines with high corrosion resistance requirements and desert environments with high wear resistance requirements, resulting in corrosion pits and wear microcracks.

[0006] A second objective of this invention is to provide a method for preparing metal flux-cored welding wire for wind turbines.

[0007] A third objective of this invention is to provide a method for using metal flux-cored welding wire for wind turbines.

[0008] The first technical solution adopted in this invention is a metal flux-cored welding wire for wind turbine generators, comprising flux powder and a welding sheath; the flux powder is composed of the following components: Ni: 58%-80%, Cr: 10%-16%, Mo: 4%-12%, Nb: 1%-3%, Fe: 2%-14%, C: 0.1%-0.2%, Mn: 0.2%-0.5%, Si: 0.2%-0.5%, and the sum of the mass percentages of the above components is 100%; the welding sheath is made of Inconel 718 alloy strip.

[0009] The first technical solution of this invention is further characterized by:

[0010] The amount of flux-cored powder in metal flux-cored welding wire is 28wt%-32wt%.

[0011] The second technical solution adopted in this invention is a method for preparing metal flux-cored welding wire for wind turbines, comprising the following steps: Step 1: Weigh the above materials according to their respective mass percentages and prepare them into powder. Step 2: Mix the powdered materials evenly and then dry them to obtain alloy powder; Step 3: Shape the alloy strip into a U-shaped groove and fill the U-shaped groove with alloy powder; Step 4: Roll the filled U-shaped alloy strip into wires, and then draw them to the predetermined diameter; Step 5: Grind the surface of the drawn wire to remove surface impurities and obtain metal-cored welding wire.

[0012] The second technical solution of the present invention is further characterized by: Step 2 specifically involves mixing the materials using a planetary ball mill and drying them in a vacuum tube furnace at 140-160℃ for 1-3 hours.

[0013] The third technical solution adopted in this invention is a method for applying metal flux-cored welding wire to wind turbines, comprising the following steps: S1. Preheat and insulate the wind turbine gear base; S2. Using cold metal transfer welding technology, under a protective gas atmosphere, the metal flux-cored welding wire is deposited and clad on the preheated substrate surface in multiple passes by lapping the adjacent two passes. After each pass is completed, the substrate temperature is allowed to drop below 250°C before the next pass is welded. S3. After each cladding pass is completed, grind the surface of the weld pass with an angle grinder; S4. Repeat S2 and S3 until the overall thickness of the cladding layer reaches 4-6mm. S5. Place the cladding workpiece into a heat-preserving furnace and slowly cool it to room temperature.

[0014] The third technical solution of this invention is further characterized by: The material of the gear base of the wind turbine in S1 is 40CrNiMoA medium carbon alloy steel; the preheating temperature to be reached is 240-260℃, and the holding time is 0.5-1.5h.

[0015] The wire reciprocating frequency for the S2 medium-cold metal transfer welding technology is set to 60-80Hz; the multi-pass deposition cladding is a three-pass deposition cladding method; the overlap between two adjacent cladding passes is 30-50%; the welding current is 160-240A, the arc voltage is 18-23V, the wire feed speed is 3-7m / min, the heat input is 0.8-1.4KJ / mm, and the welding speed is 150-420mm / min.

[0016] The protective gas in S2 is argon with a purity of ≥99.99%, and the gas flow rate is 15-20 L / min.

[0017] The slow cooling time in the S5 medium-temperature furnace shall not be less than 2 hours.

[0018] The beneficial effects of this invention are: The metal flux-cored welding wire for wind turbines provided by this invention has a convenient manufacturing process, excellent welding effect, reduced material loss, and cost savings. This welding wire can be applied to the surface modification of components such as high-end gears in gearboxes, turbine rotor shafts, and high-speed gears in wind turbines made of 40CrNiMoA medium-carbon alloy steel. Taking wind turbine gears as an example, this invention significantly improves the surface hardness, corrosion resistance, and wear resistance of the gears by preparing a nickel-based alloy cladding layer. The flux-cored welding wire is easy to prepare, accurately providing the required elemental composition and preventing defects such as oxidation and porosity. The nickel alloy strip thickness is generally 0.02mm~0.05mm, which is thinner than other alloy strips and less prone to forming brittle phases during welding. The preparation process is simpler, faster, and lower in cost compared to other methods. The flux-cored welding wire of this invention exhibits good bonding between the nickel-based cladding layer and the substrate on the surface of the wind turbine gearbox drive shaft, resulting in excellent surface performance. The arc preparation process, due to the stirring effect of the arc, makes the flux composition more uniform. CMT arc cladding technology is highly adaptable and efficient, forming a uniform and dense cladding layer that improves adhesion and hardness. The arc-based preparation process, through the stirring action of the arc, ensures a more uniform composition of the flux core. Attached Figure Description

[0019] Figure 1 This is a microstructure diagram of the nickel-based alloy flux-cored welding wire cladding in Example 5 of the present invention; Figure 2 This is a microstructure diagram of the nickel-based alloy flux-cored welding wire cladding in Example 6 of the present invention; Figure 3 This is a microstructure diagram of the nickel-based alloy flux-cored welding wire cladding in Example 7 of the present invention; Figure 4 This is a microstructure diagram of the nickel-based alloy flux-cored welding wire cladding in Example 8 of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 The metal flux-cored welding wire for wind turbines provided in this embodiment includes flux powder and a welding sheath. The flux powder is composed of the following components: Ni: 58%-80%, Cr: 10%-16%, Mo: 4%-12%, Nb: 1%-3%, Fe: 2%-14%, C: 0.1%-0.2%, Mn: 0.2%-0.5%, Si: 0.2%-0.5%, and the sum of the mass percentages of the above components is 100%. The welding sheath uses Inconel 718 alloy strip. The flux powder filling amount in the metal flux-cored welding wire is 28wt%-32wt%.

[0022] Example 2 The method for preparing the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps: Step 1: Weigh the above materials according to their respective mass percentages and prepare them into powder. Step 2: Mix the powdered materials evenly and then dry them to obtain alloy powder; Specifically, the mixture is prepared using a planetary ball mill and then dried in a vacuum tube furnace at 140-160℃ for 1-3 hours. Step 3: Shape the alloy strip into a U-shaped groove and fill the U-shaped groove with alloy powder; Step 4: Roll the filled U-shaped alloy strip into wires, and then draw them to the predetermined diameter; Step 5: Grind the surface of the drawn wire to remove surface impurities and obtain metal-cored welding wire.

[0023] Example 3 The application method of the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps, based on the aforementioned metal flux-cored welding wire for wind turbines: S1. Preheat and insulate the wind turbine gear base; The material of the wind turbine gear base is 40CrNiMoA medium carbon alloy steel; the preheating temperature should be 240-260℃, and the holding time should be 0.5-1.5h; S2. Using cold metal transfer welding technology, under a protective gas atmosphere, the metal flux-cored welding wire is deposited and clad on the preheated substrate surface in multiple passes by lapping the adjacent two passes. After each pass is completed, the substrate temperature is allowed to drop below 250°C before the next pass is welded. The reciprocating frequency of the welding wire in cold metal transfer welding technology is set to 60-80Hz; the multi-pass deposition cladding is a three-pass deposition cladding method; the overlap between two adjacent cladding passes is 30-50%; the welding current is 160-240A, the arc voltage is 18-23V, the wire feed speed is 3-7m / min, the heat input is 0.8-1.4KJ / mm, and the welding speed is 150-420mm / min; S3. After each cladding pass is completed, grind the surface of the weld pass with an angle grinder; S4. Repeat S2 and S3 until the overall thickness of the cladding layer reaches 4-6mm. S5. Place the cladding workpiece into a heat-preserving furnace and slowly cool it to room temperature.

[0024] Example 4 The application method of the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps, based on the aforementioned metal flux-cored welding wire for wind turbines: S1. Preheat and insulate the wind turbine gear base; The material of the wind turbine gear base is 40CrNiMoA medium carbon alloy steel; the preheating temperature should be 240-260℃, and the holding time should be 0.5-1.5h; S2. Using cold metal transfer welding technology, under a protective gas atmosphere, the metal flux-cored welding wire is deposited and clad on the preheated substrate surface in multiple passes by lapping the adjacent two passes. After each pass is completed, the substrate temperature is allowed to drop below 250°C before the next pass is welded. The reciprocating frequency of the welding wire in cold metal transfer welding technology is set to 60-80Hz; the multi-pass deposition cladding is a three-pass deposition cladding method; the overlap between two adjacent cladding passes is 30-50%; the welding current is 160-240A, the arc voltage is 18-23V, the wire feed speed is 3-7m / min, the heat input is 0.8-1.4KJ / mm, and the welding speed is 150-420mm / min; The protective gas is argon with a purity of ≥99.99%, and the gas flow rate is 15-20 L / min; S3. After each cladding pass is completed, grind the surface of the weld pass with an angle grinder; S4. Repeat S2 and S3 until the overall thickness of the cladding layer reaches 4-6mm. S5. Place the cladding workpiece into a heat-preserving furnace and slowly cool it to room temperature; The slow cooling time in the heat preservation furnace shall not be less than 2 hours.

[0025] Example 5 The preparation and application of the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps: Step 1: Weigh each raw material alloy powder with a purity of 99.99% or higher using an electronic scale according to the atomic mass percentage of the alloy. The composition of the raw material alloy powder, by mass percentage, is as follows: Ni: 78%, Cr: 10.9%, Mo: 4.7%, Nb: 1.9%, Fe: 2.1%, C: 0.1%, Mn: 0.2%, Si: 0.2%, and the sum of the mass percentages of the above components is 100%. Then, prepare the core powder into a powder with a mesh size of <100 mesh. Step 2: Mix the alloy powder weighed in Step 1 evenly using a planetary ball mill, and then dry it in a vacuum tube furnace at 150°C for 2 hours.

[0026] Step 3: Alloy strip rolling. After rinsing and cleaning the Inconel 718 alloy strip, dry it and then shape it into a U-shape using a forming machine. The powder is then evenly added into the U-shaped groove, with a powder filling rate of 30%. Step 4: Wire drawing and forming. The U-shaped strip is rolled into wires by rollers, and then drawn into a diameter of 1.2mm by a wire drawing machine. The surface of the welding wire is then polished with a grinding machine to remove surface impurities. Step 5: Welding cladding. Cold metal transfer welding (CMT) is used, with the wire reciprocating frequency set to 70Hz. A three-pass deposition cladding method is employed. After each cladding layer, the weld surface is ground with an angle grinder. The overlap between each cladding layer is 40%, and the overall cladding layer thickness is 5mm. The cladding layer is smooth, and the bonding strength between the cladding layer and the substrate can reach over 350MPa. Welding wire is used to clad the surface of the wind turbine gear, resulting in a cladding metal layer. The welding current is 175A, the arc voltage is 19V, the wire feed speed is 3.5m / min, the heat input is 0.8KJ / mm, and the welding speed is 150mm / min. Argon gas with a purity ≥99.99% is used as the shielding gas at a flow rate of 16L / min. A multi-pass deposition welding method is used, and the weld surface is ground with an angle grinder after each layer. Based on the above method, the microstructure of the cladding layer obtained after CMT cladding of the 40CrNiMoA medium alloy steel surface used in high-speed gears of wind turbines, after etching with a etching solution (ferric chloride and hydrochloric acid at a ratio of 1:10), is as follows: Figure 1 As shown.

[0027] Example 6 The preparation and application of the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps: Step 1: Weigh the raw material alloy powders with a purity of 99.99% or higher using an electronic scale according to the atomic mass percentage. The composition of each raw material alloy powder, by mass percentage, is as follows: Ni: 73%, Cr: 12.3%, Mo: 5.1%, Nb: 2.3%, Fe: 4.8%, C: 0.1%, Mn: 0.2%, Si: 0.2%, and the sum of the mass percentages of the above components is 100%. Then, prepare the core powder into a powder with a mesh size <100. Step 2: Mix the alloy powder weighed in Step 1 using a planetary ball mill until the powder is uniformly mixed, and then dry it in a vacuum tube furnace at 150°C for 2 hours. Step 3: Alloy strip rolling. After rinsing and cleaning the Inconel 718 alloy strip, dry it and then shape it into a U-shape using a forming machine. The powder is then evenly added into the U-shaped groove, with a powder filling rate of 30%. Step 4: Wire drawing and forming. The U-shaped strip is rolled into wires by rollers, and then drawn into a diameter of 1.2mm by a wire drawing machine. The surface of the welding wire is then polished with a grinding machine to remove surface impurities. Step 5: Welding cladding. Cold metal transfer welding (CMT) is used, with the wire reciprocating frequency set to 70Hz. A three-pass deposition cladding method is employed, and the weld surface is ground with an angle grinder after each layer. The overlap between each cladding pass is 40%. The overall cladding layer thickness is 5mm, with a smooth surface and a bonding strength to the substrate exceeding 350MPa. Welding wire is then used to clad the surface of the wind turbine gear, creating a cladding metal layer. The welding current is 185A, the arc voltage is 20V, the wire feed speed is 4m / min, the heat input is 1.0KJ / mm, and the welding speed is 180mm / min. Argon gas with a purity ≥99.99% is used as the shielding gas at a flow rate of 16L / min. A multi-pass deposition welding method is employed, and the weld surface is ground with an angle grinder after each layer. Based on the above method, the microstructure of the cladding layer obtained after CMT cladding of the 40CrNiMoA medium alloy steel surface used in high-speed gears of wind turbines, after etching with a etching solution (ferric chloride and hydrochloric acid at a ratio of 1:10), is as follows: Figure 2 As shown.

[0028] Example 7 The preparation and application of the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps: Step 1: Weigh each raw material alloy powder with a purity of 99.99% or higher using an electronic scale according to the atomic mass percentage of the alloy. The composition of each raw material alloy powder, by mass percentage, is as follows: Ni: 60%, Cr: 14%, Mo: 12%, Nb: 2.8%, Fe: 8.4%, C: 0.14%, Mn: 0.32%, Si: 0.33%, and the sum of the mass percentages of the above components is 100%. Then, prepare the core powder into a powder with a mesh size of <100 mesh. Step 2: Mix the alloy powder weighed in Step 1 using a planetary ball mill until the powder is uniformly mixed, and then dry it in a vacuum tube furnace at 150°C for 2 hours. Step 3: Alloy strip rolling. After rinsing and cleaning the Inconel 718 alloy strip, dry it and then shape it into a U-shape using a forming machine. The powder is then evenly added into the U-shaped groove, with a powder filling rate of 30%. Step 4: Wire drawing and forming. The U-shaped strip is rolled into wires by rollers, and then drawn into a diameter of 1.2mm by a wire drawing machine. The surface of the welding wire is then polished with a grinding machine to remove surface impurities. Step 5: Welding cladding. Cold metal transfer welding (CMT) is used, with the wire reciprocating frequency set to 70Hz. A three-pass deposition cladding method is employed, and the weld surface is ground with an angle grinder after each layer. The overlap between each cladding pass is 40%. The overall cladding layer thickness is 5mm, with a smooth surface and a bonding strength to the substrate exceeding 350MPa. Welding wire is used to clad the surface of the wind turbine gear, producing a cladding layer. The welding current is 210A, the arc voltage is 21V, the wire feed speed is 5m / min, the heat input is 1.2KJ / mm, and the welding speed is 240mm / min. (Ar + 2% N2) is used as the shielding gas at a flow rate of 18L / min. A multi-pass deposition welding method is employed, and the weld surface is ground with an angle grinder after each layer. Based on the above method, the microstructure of the cladding layer obtained after CMT cladding of the 40CrNiMoA medium alloy steel surface used in high-speed gears of wind turbines, after etching with a etching solution (ferric chloride and hydrochloric acid at a ratio of 1:10), is as follows: Figure 3 As shown.

[0029] Example 8 The preparation and application of the metal flux-cored welding wire for wind turbines provided in this embodiment includes the following steps: Step 1: Weigh each raw material alloy powder with a purity of 99.99% or higher using an electronic scale according to the atomic mass percentage of the alloy. The composition of each raw material alloy powder, by mass percentage, is as follows: Ni: 58%, Cr: 15.6%, Mo: 7.5%, Nb: 2.8%, Fe: 13.2%, C: 0.2%, Mn: 0.4%, Si: 0.41%, and the sum of the mass percentages of the above components is 100%. Then, prepare the core powder into a powder with a mesh size <100. Step 2: Mix the alloy powder weighed in Step 1 using a planetary ball mill until the powder is uniformly mixed, and then dry it in a vacuum tube furnace at 150°C for 2 hours. Step 3: Alloy strip rolling. After rinsing and cleaning the Inconel 718 alloy strip, dry it and then shape it into a U-shape using a forming machine. The powder is then evenly added into the U-shaped groove, with a powder filling rate of 30%. Step 4: Wire drawing and forming. The U-shaped strip is rolled into wires by rollers, and then drawn into a diameter of 1.2mm by a wire drawing machine. The surface of the welding wire is then polished with a grinding machine to remove surface impurities. Step 5: Welding cladding using cold metal transfer welding (CMT) technology. The wire reciprocating frequency is set to 70Hz, and the welding method is a three-pass deposition cladding. After each cladding layer, the weld surface needs to be ground with an angle grinder. The overlap between the previous and subsequent cladding layers is 40%. The overall thickness of the cladding layer is 5mm, the cladding layer is smooth, and the bonding strength between the cladding layer and the substrate can reach over 350MPa. Welding wire is used to clad the surface of the wind turbine gear, preparing a cladding metal layer on the wind turbine gear surface. The welding current is 220A, the arc voltage is 21.5V, the wire feed speed is 5.5m / min, the heat input is 1.3KJ / mm, the welding speed is 270mm / min, and (Ar + 2% N2) is used as the shielding gas with a flow rate of 18L / min. The welding method is a multi-pass deposition welding, and the weld surface needs to be ground with an angle grinder after each layer. Based on the above method, the microstructure of the cladding layer obtained after CMT cladding of the 40CrNiMoA medium alloy steel surface used in high-speed gears of wind turbines, after etching with a etching solution (ferric chloride and hydrochloric acid at a ratio of 1:10), is as follows: Figure 4 As shown.

[0030] Figure 1-4 The microstructures of the cladding layers obtained after CMT cladding of 40CrNiMoA medium alloy steel (used in high-speed gears for wind turbines) with different nickel-based alloy flux-cored wire contents and the cladding layers after etching with a 1:10 mixture of ferric chloride and hydrochloric acid are shown. Based on the microstructure... Figure 1 The smaller size of the lath bundles suggests that the cooling rate may be faster. Finer martensitic laths generally mean higher hardness and strength, but a slight decrease in toughness.

[0031] Figure 2 It exhibits typical lath martensite characteristics. The microstructure consists of numerous intersecting bundles of laths, which are slender and parallel. The grain boundaries and lath bundle interfaces are sensitive to the etching solution, exhibiting a darker gray hue, while the interiors of the laths are relatively brighter. Figure 2 and Figure 1 compared to, Figure 1 The structure is finer, the lamellars are shorter, and the distribution is more uniform.

[0032] Figure 3 The microstructure is finer and more uniform; although a network structure still exists, the mesh is denser, and the internal grain size is significantly smaller. Figure 4 ,and Figure 3 dendrite spacing ratio Figure 4 Smaller dendrites indicate a more uniform composition. The dark network structure is still present, but its continuity is weakened. Finer dendrites generally have better corrosion resistance.

[0033] Figure 4A distinct "dendritic" solidified structure and coarse grain boundaries running through the entire field of view are visible. The grain boundaries are severely corroded, indicating that easily corroded elements have accumulated or a second phase has formed at the grain boundaries.

[0034] All four samples with different elemental compositions were sensitive to the corrosive solution, among which Figure 3 and Figure 4 The more severe grain boundary corrosion in both samples indicates significant compositional segregation, which is common in high-alloy welding wires. The microstructure of samples 1 and 2 shows that the matrix underwent a rapid cooling and quenching process, consistent with the low heat input characteristics of CMT. The dendritic microstructure of samples 3 and 4 indicates that the cladding layer underwent rapid solidification, with sample 3 exhibiting a finer microstructure. Figure 1-4 The microstructure evolution of the CMT cladding layer from the heat-affected zone to the center of the cladding layer is fully demonstrated. Combined with the images, it can be seen that the cladding layer prepared using the nickel-based alloy flux-cored wire of the present invention has no obvious defects such as pores, cracks, or inclusions, and the cladding layer is tightly bonded to the substrate.

Claims

1. A metal flux-cored welding wire for wind turbine generators, characterized in that, It includes flux-cored powder and solder sheet; the flux-cored powder is composed of the following components: Ni: 58%-80%, Cr: 10%-16%, Mo: 4%-12%, Nb: 1%-3%, Fe: 2%-14%, C: 0.1%-0.2%, Mn: 0.2%-0.5%, Si: 0.2%-0.5%, and the sum of the mass percentages of the above components is 100%; the solder sheet is made of Inconel 718 alloy strip.

2. The metal flux-cored welding wire for wind turbines according to claim 1, characterized in that, The flux-cored wire has a flux-cored powder filling amount of 28wt%-32wt%.

3. A method for preparing metal flux-cored welding wire for wind turbines, characterized in that, The metal flux-cored welding wire for wind turbines according to claim 2 comprises the following steps: Step 1: Weigh the above materials according to their respective mass percentages and prepare them into powder. Step 2: Mix the powdered materials evenly and then dry them to obtain alloy powder; Step 3: Shape the alloy strip into a U-shaped groove and fill the U-shaped groove with alloy powder; Step 4: Roll the filled U-shaped alloy strip into wires, and then draw them to the predetermined diameter; Step 5: Grind the surface of the drawn wire to remove surface impurities and obtain metal-cored welding wire.

4. The method for preparing the metal flux-cored welding wire for wind turbines according to claim 3, characterized in that, Step 2 specifically involves mixing the materials using a planetary ball mill and drying them in a vacuum tube furnace at 140-160℃ for 1-3 hours.

5. A method for applying metal flux-cored welding wire for wind turbines, using the metal flux-cored welding wire for wind turbines as described in claim 2, characterized in that... Includes the following steps: S1. Preheat and insulate the wind turbine gear base; S2. Using cold metal transition welding technology, under a protective gas atmosphere, the metal flux-cored welding wire is deposited and clad on the preheated substrate surface in multiple passes by lapping the adjacent two passes. After each pass is completed, the substrate temperature is allowed to drop below 250°C before the next pass is welded. S3. After each cladding pass is completed, grind the surface of the weld pass with an angle grinder; S4. Repeat S2 and S3 until the overall thickness of the cladding layer reaches 4-6mm. S5. Place the cladding workpiece into a heat-preserving furnace and slowly cool it to room temperature.

6. The method for applying the metal flux-cored welding wire for wind turbines according to claim 5, characterized in that, The material of the wind turbine gear base in S1 is 40CrNiMoA medium carbon alloy steel; the preheating temperature is 240-260℃, and the heat preservation time is 0.5-1.5h.

7. The method for applying the metal flux-cored welding wire for wind turbines according to claim 5, characterized in that, The reciprocating frequency of the welding wire in the cold metal transfer welding technology described in S2 is set to 60-80Hz; the multi-pass deposition cladding is a three-pass deposition cladding method; the overlap of the two adjacent cladding passes is 30-50%; the welding current is 160-240A, the arc voltage is 18-23V, the wire feed speed is 3-7m / min, the heat input is 0.8-1.4KJ / mm, and the welding speed is 150-420mm / min.

8. The method for applying the metal flux-cored welding wire for wind turbines according to claim 5, characterized in that, The protective gas in S2 is argon with a purity of ≥99.99%, and the gas flow rate of the protective gas is 15-20 L / min.

9. The method for applying the metal flux-cored welding wire for wind turbines according to claim 5, characterized in that, The slow cooling time in the heat preservation furnace described in S5 shall not be less than 2 hours.

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