A corrosion and wear resistant slag system welding wire containing tungsten-molybdenum alloy and a preparation method thereof

Abstract

The application relates to the technical field of welding materials, and discloses a tungsten-molybdenum alloy-containing corrosion-resistant and wear-resistant slag system welding wire and a preparation method thereof. The method comprises core alloy smelting, slag system coating layer preparation, composite welding wire forming, cold processing treatment and post-treatment. Through the design of the synergistic matching of core alloy elements and the coupling mechanism of the slag system layer components, the uniform dispersion of high-density elements in the smelting process is ensured, and the component interaction of the slag system coating layer is optimized, so that the welding wire has both phase stability in a high-temperature environment and a molten slag self-regulating function, thereby solving the corrosion resistance fluctuation problem caused by element segregation in the traditional process and improving the service reliability of the welding wire under extreme working conditions. The gradient hot isostatic pressing technology is adopted to realize the physical metallurgical combination of the core and the slag system layer, so that the welding wire can maintain stable interface bonding strength in the cold and hot cycle process, the phenomenon of uneven molten slag covering in the deposition process is avoided, and the efficient transition of alloy elements and the controllability of molten pool metallurgical reaction are ensured.

Description

Technical Field

[0001] This invention relates to the field of welding materials technology, specifically to a corrosion-resistant and wear-resistant welding wire containing tungsten-molybdenum alloy and its preparation method. Background Technology

[0002] Tungsten-molybdenum alloys are alloys composed of tungsten and molybdenum. The preparation methods of tungsten-molybdenum alloys are the same as those of metallic molybdenum materials and molybdenum alloys, namely powder metallurgy sintering followed by processing and smelting processing. They can be made into rods, plates, wires or other profiles. It has been known for a long time that iron and aluminum oxides can be bound to soil and sediments, and this process may determine the decomposition of tungsten-molybdenum alloys, but few studies have quantified this process.

[0003] Currently, in the manufacturing process of tungsten-molybdenum alloy corrosion-resistant and wear-resistant slag-based welding wires, due to the high melting point characteristics of the alloy components and the complexity of the slag composition, the traditional preparation process has the following defects: During the melting stage, the density difference of tungsten and molybdenum elements causes component segregation in the molten pool, resulting in fluctuations in the cross-sectional composition of the alloy billet; When the slag coating layer is mechanically mixed, the high-hardness components such as calcium fluoride and rare earth additives cause gradient stratification due to differences in particle size and density, resulting in local component deviations in the coating layer. Especially during hot working, the mismatch of the thermal expansion coefficients between the core alloy and the slag layer induces interfacial microcracks, ultimately leading to uneven slag coverage and reduced alloy element transfer efficiency during use. These defects cause the traditional welding wire to have large fluctuations in pitting corrosion resistance in high-temperature corrosive environments and a high dispersion coefficient in the service life of the wear-resistant layer, which seriously restricts its reliability under harsh working conditions such as nuclear power and marine engineering.

[0004] Therefore, a corrosion-resistant and wear-resistant welding wire containing tungsten-molybdenum alloy and its preparation method are proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy and its preparation method, solving the problems mentioned in the background technology, such as large fluctuations in pitting corrosion resistance, high dispersion coefficient of wear-resistant layer service life, and low reliability.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a corrosion-resistant and wear-resistant welding wire containing tungsten-molybdenum alloy and its preparation method, comprising the following steps:

[0007] Step 1: Core alloy melting. Tungsten, molybdenum, chromium, nickel and niobium are melted at 1580-1680℃ for 40-80 minutes under argon protection. After adding carbon and rare earth elements, the mixture is held at the temperature for 20-40 minutes under electromagnetic stirring and then cast into an alloy billet.

[0008] Step 2: Preparation of slag coating layer. Calcium fluoride, cerium fluoride, titanium dioxide, alumina, borax, nano-yttrium oxide, and lithium carbonate are mixed and ball-milled to a particle size ≤10μm. A binder is added and granulated to prepare slag powder.

[0009] Step 3: Composite welding wire forming. After sandblasting the surface of the alloy rod blank, it is heated to 550-650℃ in a reducing atmosphere. Hot isostatic pressing is used to coat the slag powder onto the surface of the rod blank, with a pressing pressure of 120-200MPa.

[0010] Step 4: Cold working treatment, through multiple cold drawing to reduce the diameter to the target diameter, with a deformation of 8-15% per pass, and annealing treatment between each pass, with an annealing temperature of 680-750℃.

[0011] Step 5: Post-processing, after surface passivation, the wire is wound and coiled to obtain the finished welding wire.

[0012] Preferably, in step one:

[0013] During smelting, the argon gas purity is ≥99.999%, and the vacuum chamber pressure is controlled at ≤5× Pa level;

[0014] The electromagnetic stirring parameters are: frequency 15-25Hz, current intensity 200-400A, and stirring time accounting for 30-50% of the total melting time.

[0015] Directional solidification was performed using a water-cooled copper crucible with an axial temperature gradient ≥100℃ / cm and a cooling rate strictly controlled within the range of 30-50℃ / min.

[0016] Preferably, in step two:

[0017] During cryogenic ball milling with liquid nitrogen, the temperature inside the mill jar is maintained at -190°C. -170℃, the grinding media is zirconia ceramic balls, and the ball diameter ratio is Φ3mm:Φ5mm:Φ8mm=3:5:2;

[0018] The binder is a solution of polyvinyl butyral (PVB) and anhydrous ethanol at a mass ratio of 1:8-12, with a solid content of 10-15 wt%.

[0019] After granulation, the powder is sieved and classified, with a target particle size of 45-75μm and a particle size distribution concentration of D90 / D10≤2.0.

[0020] Preferably, in step three:

[0021] The reducing atmosphere is a mixture of hydrogen and nitrogen gases, in which... Volume fraction 20-25%, dew point ≤-45℃;

[0022] The hot isostatic pressing process uses a stepped heating method: first, the temperature is raised to 400℃ at a rate of 10℃ / min and held for 20 minutes, then the temperature is raised to the target temperature of 580-620℃ at a rate of 5℃ / min.

[0023] The interfacial bonding strength after lamination is ≥150MPa, and the thickness deviation of the coating layer is ≤±5%.

[0024] Preferably, in step four:

[0025] The length of the sizing zone of the cold drawing die is designed to be 3-5 times the diameter reduction, the die angle is 12-18°, and the surface roughness Ra≤0.1μm;

[0026] The lubricant is nano-molybdenum disulfide: a dispersion with a particle size of 50-100nm, a concentration of 8-12wt%, and a coating amount of 0.5-1.2g / m² per pass;

[0027] The solution treatment employs a two-stage temperature control: first, it is rapidly cooled to 300°C at 80°C / min, and then cooled to room temperature at 15°C / min.

[0028] Preferably, in step five:

[0029] The passivation solution contains 8-15 g / L chromium anhydride, 3-8 g / L sodium nitrate, and 1-4 g / L sodium molybdate, and the pH is adjusted to 3.5-5.0 with citric acid.

[0030] After passivation, a passivation film with a thickness of 0.8-1.5 μm is formed, and the Cr / Fe atomic ratio in the film is ≥2.5;

[0031] Dynamic control of winding tension: Yield strength is tested once every 10 meters, and the tension is adjusted in real time to 8-12%σs.

[0032] Preferably, after step five, the method further includes:

[0033] Micro-arc oxidation strengthening treatment involves immersing the passivated welding wire in an electrolyte, applying a voltage of 280-350V using a dual-pulse power supply, a frequency of 400-800Hz, a positive-to-negative pulse ratio of 1:2-3, and a treatment time of 8-15 minutes.

[0034] The electrolyte composition is: sodium tungstate 20-40 g / L, potassium silicate 10-25 g / L, trisodium citrate 5-12 g / L, ammonium molybdate 2-8 g / L, and the temperature is controlled at 20-35℃.

[0035] After treatment, a composite ceramic layer with a thickness of 0.5-2 μm is formed on the surface of the welding wire. and The mass ratio is 3.0-5.5:1.

[0036] Preferably, the welding wire consists of a core alloy and an outer slag layer;

[0037] The core alloy contains the following components by weight percentage: tungsten 12-18%, molybdenum 8-15%, chromium 4.2-6.8%, nickel 3.5-5.5%, carbon 0.05-0.12%, niobium 0.8-1.6%, rare earth elements 0.03-0.15%, with the balance being iron and unavoidable impurities;

[0038] The outer slag layer accounts for 10-25% of the total weight of the welding wire, and its raw materials include, by weight: 35-50 parts calcium fluoride, 10-18 parts cerium fluoride, 5-12 parts titanium dioxide, 3-8 parts alumina, 2-7 parts borax, 1-4 parts nano yttrium oxide, and 0.5-2 parts lithium carbonate.

[0039] The welding wire has a tensile strength ≥620MPa, a corrosion weight loss rate ≤0.15mg / cm² after immersion in 5wt% NaCl solution for 30 days, and a high-temperature wear rate ≤3.5× mm³ / N·m.

[0040] Preferably, in the core alloy:

[0041] The weight ratio of tungsten to molybdenum is controlled at 1.3-1.8:1;

[0042] The rare earth elements are a blend of lanthanum, cerium, and yttrium in a ratio of 4-6:3-5:1;

[0043] Impurities that are unavoidable include sulfur content ≤0.008% and phosphorus content ≤0.010%.

[0044] Preferably, the outer slag layer raw material further comprises:

[0045] Calcium fluoride is produced using high-purity spherical particles with a particle size D50 of 15-35 μm.

[0046] The weight ratio of cerium fluoride to nano-yttrium oxide is 2.5-4.0:1;

[0047] Add 0.5-3 parts by weight of zircon powder .

[0048] (III) Beneficial Effects

[0049] Compared with the prior art, the present invention provides a corrosion-resistant and wear-resistant welding wire containing tungsten-molybdenum alloy and its preparation method, which has the following beneficial effects:

[0050] 1. In this invention, when preparing tungsten-molybdenum alloy corrosion-resistant and wear-resistant slag-based welding wire, the synergistic ratio between core alloying elements and the coupling mechanism of slag layer components are designed to ensure the uniform dispersion of high-density elements during the smelting process. At the same time, the interaction between slag coating layer components is optimized, so that the welding wire has both phase stability under high temperature environment and slag self-regulation function. This solves the problem of corrosion resistance fluctuation caused by element segregation in traditional processes and improves the service reliability of welding wire under extreme working conditions.

[0051] 2. In this invention, in the process of controlling the composite interface of the welding wire, gradient hot isostatic pressing technology is used to achieve physical metallurgical bonding between the core and the slag layer, which overcomes the risk of interface defects caused by the difference in thermal expansion of materials, so that the welding wire maintains a stable interface bonding strength during the hot and cold cycle, avoids uneven slag coverage during the deposition process, and ensures efficient transition of alloying elements and controllability of the metallurgical reaction of the molten pool.

[0052] 3. In this invention, by establishing a multi-level post-processing chain, and coordinating cold working deformation strengthening, solid solution strengthening and surface ceramic modification technologies, a gradient functional protective layer is formed on the surface of the welding wire. This enables the welding wire to autonomously repair surface micro-damage under wear-corrosion interaction conditions, while strengthening the synergistic wear resistance mechanism of the core components. This breaks through the performance bottleneck of single protection methods and improves the service life and environmental adaptability of the welded parts. Attached Figure Description

[0053] Figure 1 This is a flowchart illustrating a corrosion-resistant and wear-resistant welding wire containing a tungsten-molybdenum alloy and its preparation method, according to the present invention. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] Example 1: A corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy and its preparation method, comprising the following steps:

[0056] Step 1: Core alloy melting. Tungsten, molybdenum, chromium, nickel and niobium are melted at 1580℃ for 40 minutes under argon protection. After adding carbon and rare earth elements, the mixture is kept at the temperature for 20 minutes under electromagnetic stirring and then cast into an alloy billet.

[0057] Step 2: Preparation of slag coating layer. Calcium fluoride, cerium fluoride, titanium dioxide, alumina, borax, nano-yttrium oxide, and lithium carbonate are mixed and ball-milled to a particle size ≤10μm. A binder is added and granulated to prepare slag powder.

[0058] Step 3: Composite welding wire forming. After sandblasting the surface of the alloy billet, it is heated to 550°C in a reducing atmosphere. Hot isostatic pressing is used to coat the slag powder onto the surface of the billet, with a pressing pressure of 120MPa.

[0059] Step 4: Cold working treatment, through multiple cold drawing to reduce the diameter to the target diameter, with a deformation amount of 8% per pass, and annealing treatment between each pass, with an annealing temperature of 680℃;

[0060] Step 5: Post-processing, after surface passivation, the wire is wound and coiled to obtain the finished welding wire.

[0061] In step one:

[0062] During smelting, the argon gas purity is ≥99.999%, and the vacuum chamber pressure is controlled at ≤5× Pa level;

[0063] The electromagnetic stirring parameters are: frequency 15Hz, current intensity 200A, and stirring time accounting for 30% of the total melting time.

[0064] Directional solidification was performed using a water-cooled copper crucible with an axial temperature gradient ≥100℃ / cm and a cooling rate strictly controlled within the range of 30℃ / min.

[0065] In step two:

[0066] During cryogenic ball milling with liquid nitrogen, the temperature inside the mill jar is maintained at -190°C. ℃, the grinding media are zirconia ceramic balls, and the ball diameter ratio is Φ3mm:Φ5mm:Φ8mm=3:5:2;

[0067] The binder is a solution of polyvinyl butyral (PVB) and anhydrous ethanol in a 1:8 mass ratio, with a solid content of 10 wt%.

[0068] After granulation, the powder is sieved and classified, with a target particle size of 45μm and a particle size distribution concentration of D90 / D10 ≤ 2.0.

[0069] In step three:

[0070] The reducing atmosphere is a mixture of hydrogen and nitrogen gases, in which... Volumetric weight percentage 20%, dew point ≤ -45℃;

[0071] The hot isostatic pressing process uses a stepped heating method: first, the temperature is raised to 400℃ at a rate of 10℃ / min and held for 20 minutes, then the temperature is raised to the target temperature of 580℃ at a rate of 5℃ / min.

[0072] The interfacial bonding strength after lamination is ≥150MPa, and the thickness deviation of the coating layer is ≤±5%.

[0073] In step four:

[0074] The length of the sizing zone of the cold drawing die is designed to be 3 times the diameter reduction, the die angle is 12°, and the surface roughness Ra≤0.1μm;

[0075] The lubricant is nano-molybdenum disulfide: a dispersion with a particle size of 50 nm and a concentration of 8 wt%, with a coating amount of 0.5 g / m² per pass;

[0076] The solution treatment employs a two-stage temperature control: first, it is rapidly cooled to 300°C at 80°C / min, and then cooled to room temperature at 15°C / min.

[0077] In step five:

[0078] The passivation solution contains 8 g / L chromium anhydride, 3 g / L sodium nitrate, and 1 g / L sodium molybdate, and the pH is adjusted to 3.5 with citric acid.

[0079] After passivation, a passivation film with a thickness of 0.8 μm is formed, and the Cr / Fe atomic ratio in the film is ≥2.5;

[0080] Dynamic control of winding tension: Yield strength is tested once every 10 meters, and the tension is adjusted to 8%σs in real time.

[0081] Step five is followed by:

[0082] Micro-arc oxidation strengthening treatment involves immersing the passivated welding wire in an electrolyte, applying a 280V voltage with a frequency of 400Hz using a dual-pulse power supply, a positive-to-negative pulse ratio of 1:2, and a treatment time of 8 minutes.

[0083] The electrolyte composition is: sodium tungstate 20g / L, potassium silicate 10g / L, trisodium citrate 5g / L, ammonium molybdate 2g / L, and the temperature is controlled at 20℃;

[0084] After treatment, a composite ceramic layer with a thickness of 0.5 μm is formed on the surface of the welding wire. and The mass ratio is 3.0:1.

[0085] The welding wire consists of a core alloy and an outer slag layer;

[0086] The core alloy contains the following components by weight percentage: 12% tungsten, 8% molybdenum, 4.2% chromium, 3.5% nickel, 0.05% carbon, 0.8% niobium, 0.03% rare earth elements, with the balance being iron and unavoidable impurities;

[0087] The outer slag layer accounts for 10% of the total weight of the welding wire, and its raw materials, by weight, include: 35 parts calcium fluoride, 10 parts cerium fluoride, 5 parts titanium dioxide, 3 parts alumina, 2 parts borax, 1 part nano yttrium oxide, and 0.5 parts lithium carbonate.

[0088] The welding wire has a tensile strength ≥620MPa, a corrosion weight loss rate ≤0.15mg / cm² after immersion in 5wt% NaCl solution for 30 days, and a high-temperature wear rate ≤3.5× mm³ / N·m.

[0089] In core alloy:

[0090] The weight ratio of tungsten to molybdenum is controlled at 1.3:1;

[0091] The rare earth elements are a blend of lanthanum, cerium, and yttrium in a ratio of 4:3:1;

[0092] Impurities that are unavoidable include sulfur content ≤0.008% and phosphorus content ≤0.010%.

[0093] The outer slag layer raw material further includes:

[0094] Calcium fluoride is produced using high-purity spherical particles with a particle size D50 of 15 μm.

[0095] The weight ratio of cerium fluoride to nano-yttrium oxide is 2.5:1;

[0096] Add 0.5 parts by weight of zircon powder .

[0097] Example 2: A corrosion-resistant and wear-resistant welding wire containing tungsten-molybdenum alloy and its preparation method, comprising the following steps:

[0098] Step 1: Core alloy melting. Tungsten, molybdenum, chromium, nickel and niobium are melted at 1630℃ for 60 minutes under argon protection. After adding carbon and rare earth elements, the mixture is kept at the temperature for 30 minutes under electromagnetic stirring and then cast into an alloy billet.

[0099] Step 2: Preparation of slag coating layer. Calcium fluoride, cerium fluoride, titanium dioxide, alumina, borax, nano-yttrium oxide, and lithium carbonate are mixed and ball-milled to a particle size ≤10μm. A binder is added and granulated to prepare slag powder.

[0100] Step 3: Composite welding wire forming. After sandblasting the surface of the alloy rod blank, it is heated to 600℃ in a reducing atmosphere. Hot isostatic pressing is used to coat the slag powder onto the surface of the rod blank, with a pressing pressure of 160MPa.

[0101] Step 4: Cold working treatment, through multiple cold drawing to reduce the diameter to the target diameter, with a deformation amount of 11% per pass, and annealing treatment between each pass, with an annealing temperature of 715℃.

[0102] Step 5: Post-processing, after surface passivation, the wire is wound and coiled to obtain the finished welding wire.

[0103] In step one:

[0104] During smelting, the argon gas purity is ≥99.999%, and the vacuum chamber pressure is controlled at ≤5× Pa level;

[0105] The electromagnetic stirring parameters are: frequency 20Hz, current intensity 300A, and stirring time accounting for 40% of the total melting time;

[0106] Directional solidification was performed using a water-cooled copper crucible with an axial temperature gradient ≥100℃ / cm and a cooling rate strictly controlled within the range of 40℃ / min.

[0107] In step two:

[0108] During liquid nitrogen cryogenic ball milling, the temperature inside the grinding jar is maintained at -180℃, and the grinding media is zirconia ceramic balls with a ball diameter ratio of Φ3mm:Φ5mm:Φ8mm=3:5:2.

[0109] The binder is a solution of polyvinyl butyral (PVB) and anhydrous ethanol at a mass ratio of 1:10, with a solid content of 13 wt%.

[0110] After granulation, the powder is sieved and classified, with a target particle size of 60μm and a particle size distribution concentration of D90 / D10 ≤ 2.0.

[0111] In step three:

[0112] The reducing atmosphere is a mixture of hydrogen and nitrogen gases, in which... Volume ratio 23%, dew point ≤ -45℃;

[0113] The hot isostatic pressing process uses a stepped heating method: first, the temperature is raised to 400℃ at a rate of 10℃ / min and held for 20 minutes, then the temperature is raised to the target temperature of 600℃ at a rate of 5℃ / min.

[0114] The interfacial bonding strength after lamination is ≥150MPa, and the thickness deviation of the coating layer is ≤±5%.

[0115] In step four:

[0116] The length of the sizing zone of the cold drawing die is designed to be 4 times the diameter reduction, the die angle is 15°, and the surface roughness Ra≤0.1μm;

[0117] The lubricant is nano-molybdenum disulfide: a dispersion with a particle size of 75nm, a concentration of 10wt%, and a coating amount of 0.8g / m² per pass;

[0118] The solution treatment employs a two-stage temperature control: first, it is rapidly cooled to 300°C at 80°C / min, and then cooled to room temperature at 15°C / min.

[0119] In step five:

[0120] The passivation solution contains 11 g / L chromium anhydride, 5 g / L sodium nitrate, and 3 g / L sodium molybdate, and the pH is adjusted to 4.5 with citric acid.

[0121] After passivation, a passivation film with a thickness of 1.2 μm is formed, and the Cr / Fe atomic ratio in the film is ≥2.5;

[0122] Dynamic control of winding tension: Yield strength is tested once every 10 meters, and the tension is adjusted to 10%σs in real time.

[0123] Step five is followed by:

[0124] Micro-arc oxidation strengthening treatment involves immersing the passivated welding wire in an electrolyte solution, applying a voltage of 280-350V using a dual-pulse power supply at a frequency of 600Hz, a positive-to-negative pulse ratio of 1:2.5, and a treatment time of 12 minutes.

[0125] The electrolyte composition is: sodium tungstate 30g / L, potassium silicate 17g / L, trisodium citrate 8g / L, ammonium molybdate 5g / L, and the temperature is controlled at 27℃;

[0126] After treatment, a 1.2 μm thick composite ceramic layer is formed on the surface of the welding wire. and The mass ratio is 4.8:1.

[0127] The welding wire consists of a core alloy and an outer slag layer;

[0128] The core alloy contains the following components by weight percentage: 15% tungsten, 12% molybdenum, 5.4% chromium, 4.5% nickel, 0.08% carbon, 0.8-1.6% niobium, 0.09% rare earth elements, with the balance being iron and unavoidable impurities;

[0129] The outer slag layer accounts for 18% of the total weight of the welding wire, and its raw materials by weight include: 43 parts calcium fluoride, 14 parts cerium fluoride, 9 parts titanium dioxide, 6 parts alumina, 5 parts borax, 3 parts nano yttrium oxide, and 1.4 parts lithium carbonate.

[0130] The welding wire has a tensile strength ≥620MPa, a corrosion weight loss rate ≤0.15mg / cm² after immersion in 5wt% NaCl solution for 30 days, and a high-temperature wear rate ≤3.5× mm³ / N·m.

[0131] In core alloy:

[0132] The weight ratio of tungsten to molybdenum is controlled at 1.5:1;

[0133] The rare earth elements are a blend of lanthanum, cerium, and yttrium in a ratio of 5:4:1;

[0134] Impurities that are unavoidable include sulfur content ≤0.008% and phosphorus content ≤0.010%.

[0135] The outer slag layer raw material further includes:

[0136] Calcium fluoride is produced using high-purity spherical particles with a particle size D50 of 25 μm.

[0137] The weight ratio of cerium fluoride to nano-yttrium oxide is 3.2:1;

[0138] Add 1.5 parts by weight of zircon powder .

[0139] Example 3: A corrosion-resistant and wear-resistant welding wire containing tungsten-molybdenum alloy and its preparation method, comprising the following steps:

[0140] Step 1: Core alloy melting. Tungsten, molybdenum, chromium, nickel and niobium are melted at 1680℃ for 80 minutes under argon protection. After adding carbon and rare earth elements, the mixture is held at the temperature for 40 minutes under electromagnetic stirring and then cast into an alloy billet.

[0141] Step 2: Preparation of slag coating layer. Calcium fluoride, cerium fluoride, titanium dioxide, alumina, borax, nano-yttrium oxide, and lithium carbonate are mixed and ball-milled to a particle size ≤10μm. A binder is added and granulated to prepare slag powder.

[0142] Step 3: Composite welding wire forming. After sandblasting the surface of the alloy rod blank, it is heated to 650°C in a reducing atmosphere. Hot isostatic pressing is used to coat the slag powder onto the surface of the rod blank, with a pressing pressure of 200MPa.

[0143] Step 4: Cold working treatment, through multiple cold drawing to reduce the diameter to the target diameter, with a deformation amount of 15% per pass, and annealing treatment between each pass, with an annealing temperature of 50℃;

[0144] Step 5: Post-processing, after surface passivation, the wire is wound and coiled to obtain the finished welding wire.

[0145] In step one:

[0146] During smelting, the argon gas purity is ≥99.999%, and the vacuum chamber pressure is controlled at ≤5× Pa level;

[0147] The electromagnetic stirring parameters are: frequency 25Hz, current intensity 400A, and stirring time accounting for 50% of the total melting time;

[0148] Directional solidification was performed using a water-cooled copper crucible with an axial temperature gradient ≥100℃ / cm and a cooling rate strictly controlled within the range of 50℃ / min.

[0149] In step two:

[0150] During cryogenic ball milling with liquid nitrogen, the temperature inside the mill jar is maintained at -170℃. The milling media are zirconia ceramic balls with a ball diameter ratio of Φ3mm:Φ5mm:Φ8mm=3:5:2.

[0151] The binder is a solution of polyvinyl butyral (PVB) and anhydrous ethanol at a mass ratio of 1:12, with a solid content of 15 wt%.

[0152] After granulation, the powder is sieved and classified, with a target particle size of 75μm and a particle size distribution concentration of D90 / D10 ≤ 2.0.

[0153] In step three:

[0154] The reducing atmosphere is a mixture of hydrogen and nitrogen gases, in which... Volume fraction 25%, dew point ≤-45℃;

[0155] The hot isostatic pressing process uses a stepped heating method: first, the temperature is raised to 400℃ at a rate of 10℃ / min and held for 20 minutes, then the temperature is raised to the target temperature of 620℃ at a rate of 5℃ / min.

[0156] The interfacial bonding strength after lamination is ≥150MPa, and the thickness deviation of the coating layer is ≤±5%.

[0157] In step four:

[0158] The length of the sizing zone of the cold drawing die is designed to be 5 times the diameter reduction, the die angle is 18°, and the surface roughness Ra≤0.1μm;

[0159] The lubricant is nano-molybdenum disulfide: a dispersion with a particle size of 100nm, a concentration of 12wt%, and a coating amount of 1.2g / m² per pass;

[0160] The solution treatment employs a two-stage temperature control: first, it is rapidly cooled to 300°C at 80°C / min, and then cooled to room temperature at 15°C / min.

[0161] In step five:

[0162] The passivation solution contains 15 g / L chromium anhydride, 8 g / L sodium nitrate, and 4 g / L sodium molybdate, and the pH is adjusted to 5.0 with citric acid.

[0163] After passivation, a passivation film with a thickness of 1.5 μm is formed, and the Cr / Fe atomic ratio in the film is ≥2.5;

[0164] Dynamic control of winding tension: Yield strength is tested once every 10 meters, and the tension is adjusted to 12%σs in real time.

[0165] Step five is followed by:

[0166] Micro-arc oxidation strengthening treatment involves immersing the passivated welding wire in an electrolyte, applying a 350V voltage with a frequency of 800Hz and a positive-to-negative pulse ratio of 1:3 using a dual-pulse power supply, and treating for 15 minutes.

[0167] The electrolyte composition is: sodium tungstate 40g / L, potassium silicate 25g / L, trisodium citrate 12g / L, ammonium molybdate 8g / L, and the temperature is controlled at 35℃.

[0168] After treatment, a 2μm thick composite ceramic layer is formed on the surface of the welding wire. and The mass ratio is 5.5:1.

[0169] The welding wire consists of a core alloy and an outer slag layer;

[0170] The core alloy contains the following components by weight percentage: 18% tungsten, 15% molybdenum, 6.8% chromium, 5.5% nickel, 0.12% carbon, 1.6% niobium, 0.15% rare earth elements, with the balance being iron and unavoidable impurities;

[0171] The outer slag layer accounts for 25% of the total weight of the welding wire, and its raw materials include, by weight: 50 parts calcium fluoride, 18 parts cerium fluoride, 12 parts titanium dioxide, 8 parts alumina, 7 parts borax, 4 parts nano yttrium oxide, and 2 parts lithium carbonate.

[0172] The welding wire has a tensile strength ≥620MPa, a corrosion weight loss rate ≤0.15mg / cm² after immersion in 5wt% NaCl solution for 30 days, and a high-temperature wear rate ≤3.5× mm³ / N·m.

[0173] In core alloy:

[0174] The weight ratio of tungsten to molybdenum is controlled at 1.8:1;

[0175] The rare earth elements are a blend of lanthanum, cerium, and yttrium in a ratio of 6:5:1;

[0176] Impurities that are unavoidable include sulfur content ≤0.008% and phosphorus content ≤0.010%.

[0177] The outer slag layer raw material further includes:

[0178] Calcium fluoride is produced using high-purity spherical particles with a particle size D50 of 35 μm.

[0179] The weight ratio of cerium fluoride to nano-yttrium oxide is 4.0:1;

[0180] Add 3 parts by weight of zircon powder .

[0181] Comparative Example 1: The difference between this comparative example and Example 1 is that niobium was not added when smelting the core alloy in this comparative example.

[0182] Comparative Example 2 differs from Example 1 in that nano-yttrium oxide was not added during the preparation of the slag layer in this comparative example.

[0183] Comparative Example 3 differs from Example 1 in that it did not undergo micro-arc oxidation enhancement treatment.

[0184] Comparative Example 4 differs from Example 1 in that it uses conventional cold-pressing coating technology instead of hot isostatic pressing.

[0185] The welding wires prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The test items and test methods are as follows:

[0186] Corrosion resistance test: Immerse in 5wt% NaCl solution for 30 days and measure the weight loss per unit area due to corrosion.

[0187] High-temperature wear resistance test: The volumetric wear rate was calculated using a reciprocating friction and wear tester at 600℃ with a load of 50N and a sliding speed of 0.2m / s.

[0188] Tensile strength test: using an electronic universal testing machine, tensile rate 2 mm / min;

[0189] Interface bonding strength test: The bonding force between the core and the slag layer is determined by a shear tester.

[0190] The test data for the welding wires prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below:

[0191]

[0192] Comparison and analysis of the data in the table show that the tungsten-molybdenum alloy welding wires prepared using the processes of Examples 1-3 exhibit significantly superior performance compared to Comparative Examples 1-4. This indicates that in preparing tungsten-molybdenum alloy corrosion-resistant and wear-resistant slag-based welding wires, by designing the synergistic ratio between core alloying elements and the coupling mechanism of slag layer components, the uniform dispersion of high-density elements during the smelting process is ensured. Simultaneously, the interaction of slag coating components is optimized, enabling the welding wire to possess both phase stability under high-temperature environments and slag self-regulation capabilities. This solves the corrosion resistance fluctuation problem caused by element segregation in traditional processes, improving the service reliability of the welding wire under extreme conditions. In the composite interface control stage, gradient hot isostatic pressing technology is used to achieve physical metallurgical bonding between the core and the slag layer, overcoming the challenges caused by differences in material thermal expansion. The risk of interface defects is mitigated, ensuring that the welding wire maintains stable interfacial bonding strength during thermal cycling, avoiding uneven slag coverage during deposition, and guaranteeing efficient transition of alloying elements and controllable metallurgical reaction in the molten pool. By establishing a multi-level post-processing chain, and coordinating cold working deformation strengthening, solid solution strengthening, and surface ceramic modification technologies, a gradient functional protective layer is formed on the surface of the welding wire. This allows the welding wire to autonomously repair surface micro-damage under wear-corrosion interaction conditions, while strengthening the synergistic wear resistance mechanism of the core components. This overcomes the performance bottleneck of single protection methods and improves the service life and environmental adaptability of the welded parts.

[0193] By comparing and analyzing the relevant data in the table, it can be seen that the tungsten-molybdenum alloy corrosion-resistant and wear-resistant slag-resistant welding wire prepared by the process of this invention not only has excellent corrosion resistance, high-temperature wear resistance, and stable mechanical properties, but also demonstrates that the tungsten-molybdenum alloy corrosion-resistant and wear-resistant slag-resistant welding wire and its preparation method provided by this invention have a broader market prospect and are more suitable for promotion.

[0194] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0195] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a corrosion-resistant and wear-resistant welding wire containing a tungsten-molybdenum alloy, characterized in that: Includes the following steps: Step 1: Core alloy melting. Tungsten, molybdenum, chromium, nickel and niobium are melted at 1580-1680℃ for 40-80 minutes under argon protection. After adding carbon and rare earth elements, the mixture is held at the temperature for 20-40 minutes under electromagnetic stirring and then cast into an alloy billet. The core alloy contains the following components by weight percentage: tungsten 12-18%, molybdenum 8-15%, chromium 4.2-6.8%, nickel 3.5-5.5%, carbon 0.05-0.12%, niobium 0.8-1.6%, rare earth elements 0.03-0.15%, with the balance being iron and unavoidable impurities; Step 2: Preparation of slag coating layer. Calcium fluoride, cerium fluoride, titanium dioxide, alumina, borax, nano-yttrium oxide, and lithium carbonate are mixed and ball-milled to a particle size ≤10μm. A binder is added and granulated to prepare slag powder. The raw materials for the slag coating layer, by weight, include: 35-50 parts calcium fluoride, 10-18 parts cerium fluoride, 5-12 parts titanium dioxide, 3-8 parts alumina, 2-7 parts borax, 1-4 parts nano yttrium oxide, and 0.5-2 parts lithium carbonate; Step 3: Composite welding wire forming. After sandblasting the surface of the alloy rod blank, it is heated to 550-650℃ in a reducing atmosphere. Hot isostatic pressing is used to coat the slag powder onto the surface of the rod blank, with a pressing pressure of 120-200MPa. Step 4: Cold working treatment, through multiple cold drawing to reduce the diameter to the target diameter, with a deformation of 8-15% per pass, and annealing treatment between each pass, with an annealing temperature of 680-750℃. Step 5: Post-processing, after surface passivation, the wire is wound and coiled to obtain the finished welding wire.

2. The method for preparing a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 1, characterized in that: In step one: During smelting, the argon gas purity is ≥99.999%, and the vacuum chamber pressure is controlled at... The electromagnetic stirring parameters are: frequency 15-25Hz, current intensity 200-400A, and stirring time accounting for 30-50% of the total melting time. Directional solidification was performed using a water-cooled copper crucible with an axial temperature gradient ≥100℃ / cm and a cooling rate strictly controlled within the range of 30-50℃ / min.

3. The method for preparing a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 1, characterized in that: In step two: During cryogenic ball milling with liquid nitrogen, the temperature inside the grinding jar is maintained. The milling media consisted of zirconia ceramic balls with a diameter ratio of Φ3mm:Φ5mm:Φ8mm = 3:5:2; the binder was a solution of polyvinyl butyral (PVB) and anhydrous ethanol at a mass ratio of 1:8-12, with a solid content of 10-15 wt%. After granulation, the powder is sieved and classified, with a target particle size of 45-75μm and a particle size distribution concentration of D90 / D10≤2.

0.

4. The method for preparing a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 1, characterized in that: In step three: The reducing atmosphere is a mixture of hydrogen and nitrogen gases, in which... Volume ratio 20-25%, dew point ≤-45℃; hot isostatic pressing process adopts stepped heating: first heat to 400℃ at 10℃ / min and hold for 20min, then heat to the target temperature of 580-620℃ at 5℃ / min; after pressing, the interface bonding strength is ≥150MPa, and the coating thickness deviation is ≤±5%.

5. The method for preparing a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 1, characterized in that: In step four: The length of the sizing zone of the cold drawing die is designed to be 3-5 times the diameter reduction, the die angle is 12-18°, and the surface roughness Ra≤0.1μm; The lubricant is nano-molybdenum disulfide: a dispersion with a particle size of 50-100nm and a concentration of 8-12wt%, with a coating amount of 0.5-1.2g / m² per pass; the solution treatment adopts a two-stage temperature control: first, it is rapidly cooled to 300℃ at 80℃ / min, and then cooled to room temperature at 15℃ / min.

6. The method for preparing a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 1, characterized in that: In step five: The passivation solution contains 8-15 g / L chromium anhydride, 3-8 g / L sodium nitrate, and 1-4 g / L sodium molybdate, and the pH is adjusted to 3.5-5.0 with citric acid. After passivation, a passivation film with a thickness of 0.8-1.5 μm is formed, and the Cr / Fe atomic ratio in the film is ≥2.5; Dynamic control of winding tension: Yield strength is tested once every 10 meters, and the tension is adjusted in real time to 8-12%σs.

7. The method for preparing a corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 1, characterized in that: Step five is followed by: Micro-arc oxidation strengthening treatment involves immersing the passivated welding wire in an electrolyte, applying a voltage of 280-350V using a dual-pulse power supply, a frequency of 400-800Hz, a positive-to-negative pulse ratio of 1:2-3, and a treatment time of 8-15 minutes. The electrolyte composition is: sodium tungstate 20-40 g / L, potassium silicate 10-25 g / L, trisodium citrate 5-12 g / L, ammonium molybdate 2-8 g / L, and the temperature is controlled at 20-35℃. After treatment, a composite ceramic layer with a thickness of 0.5-2 μm is formed on the surface of the welding wire. and The mass ratio is 3.0-5.5:

1.

8. A tungsten-molybdenum alloy-containing corrosion-resistant and wear-resistant slag-resistant welding wire, used to implement the preparation method of the tungsten-molybdenum alloy-containing corrosion-resistant and wear-resistant slag-resistant welding wire according to any one of claims 1-7, characterized in that: It consists of a core alloy and an outer slag system; The core alloy contains the following components by weight percentage: tungsten 12-18%, molybdenum 8-15%, chromium 4.2-6.8%, nickel 3.5-5.5%, carbon 0.05-0.12%, niobium 0.8-1.6%, rare earth elements 0.03-0.15%, with the balance being iron and unavoidable impurities; The outer slag layer accounts for 10-25% of the total weight of the welding wire, and its raw materials include, by weight: 35-50 parts calcium fluoride, 10-18 parts cerium fluoride, 5-12 parts titanium dioxide, 3-8 parts alumina, 2-7 parts borax, 1-4 parts nano yttrium oxide, and 0.5-2 parts lithium carbonate. The tensile strength of the welding wire ,exist Corrosion weight loss rate after immersion in solution for 30 days High temperature wear rate .

9. The corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 8, characterized in that: In the core alloy: The weight ratio of tungsten to molybdenum is controlled at 1.3-1.8:1; The rare earth elements are a blend of lanthanum, cerium, and yttrium in a ratio of 4-6:3-5:1; Impurities that are unavoidable include sulfur content ≤0.008% and phosphorus content ≤0.010%.

10. The corrosion-resistant and wear-resistant slag-resistant welding wire containing tungsten-molybdenum alloy according to claim 8, characterized in that: The outer slag layer raw material further comprises: Calcium fluoride is produced using high-purity spherical particles with a particle size D50 of 15-35 μm. The weight ratio of cerium fluoride to nano-yttrium oxide is 2.5-4.0:1; Add 0.5-3 parts by weight of zircon powder .

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