Wear-resistant flux-cored wire and manufacturing method thereof

Abstract

The invention discloses a wear-resistant flux-cored wire and a manufacturing method thereof, and belongs to the technical field of welding materials, the wear-resistant flux-cored wire is formed by wrapping three layers of flux cores with a low-carbon steel strip, the inner main wear-resistant layer contains chromium carbide, recycled slag, cobalt-based alloy and carbon nanofibers, and the outer main wear-resistant layer contains chromium carbide, recycled slag, cobalt-based alloy and carbon nanofibers; the gradient mixing layer is in gradient transition of inner and outer layer components; and the outer auxiliary wear-resistant layer contains tungsten carbide, ferrovanadium and electrolytic manganese powder. The preparation method comprises the steps of waste residue recovery treatment, ultrasonic dispersion and mixing, layered vibration compaction and cold drawing forming. Through three-layer structure collaboration, nano reinforcement and solid waste recovery, the wear resistance is improved by 20%-30%, the cost is reduced by 15%-20%, and the composite material is suitable for complex working conditions such as mines and metallurgy and has the advantages of being high in bonding strength, resistant to cracks, stable in process and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding materials, and particularly relates to a wear-resistant flux-cored wire and a manufacturing method thereof. Background Art

[0002] Wear-resistant flux-cored wires are widely used in heavy industries such as mining, metallurgy, cement, and construction machinery for surface strengthening and wear repair of key components. With the development of industrial equipment towards high load, long life, and complexity, higher requirements are put forward for the wear resistance, crack resistance, and process stability of the wires. The current technology has the following disadvantages: insufficient wear resistance, local wear is too fast due to single-layer or simple composite structures, and it is difficult to adapt to complex working conditions; low material utilization rate, imperfect welding slag recycling process, and serious resource waste; poor process performance, poor slag fluidity, unstable arc, affecting welding quality, uneven dispersion of nanomaterials: reinforcing phases such as carbon fiber are prone to agglomeration, weakening the material performance. Summary of the Invention

[0003] In view of the above pain points, the present invention provides a wear-resistant flux-cored wire and a manufacturing method thereof, which comprehensively improve wear resistance, process stability, and environmental protection through the collaborative design of inner-middle-outer three-layer materials, high-value utilization of recycled slag, and ultrasonic dispersion process.

[0004] The solution of the present invention is as follows:

[0005] A wear-resistant flux-cored wire, comprising a steel strip shell and a flux core filled in the steel strip, characterized in that:

[0006] The flux core is sequentially divided into an inner main wear-resistant layer, a gradient mixing zone, and an outer auxiliary wear-resistant layer from the inside to the outside along the cross-section direction;

[0007] The inner main wear-resistant layer accounts for 55%-60% of the total thickness of the flux core, and by weight percentage, it includes: 30%-35% of chromium carbide particles, 40%-50% of recycled slag powder, 5%-8% of cobalt-based alloy powder, 3%-5% of nano-carbon fiber, and the balance of auxiliary additives; the auxiliary additives include one or more of a binder, a slag former, or a deoxidizer;

[0008] The gradient mixing zone accounts for 10%-15% of the total thickness of the flux core, and contains a mixed powder of 50%-70% of the components of the inner main wear-resistant layer and 30%-50% of the components of the outer auxiliary wear-resistant layer. The particle size ratio of chromium carbide particles to tungsten carbide particles in the mixed powder is 2-3:1, and the distribution density of nano-carbon fiber in the mixed powder is not less than 5×10 5 per cubic centimeter;

[0009] The outer auxiliary wear-resistant layer accounts for 25%-30% of the total thickness of the flux-cored wire, and by weight percentage includes: 25%-30% tungsten carbide particles, 10%-15% ferrovanadium alloy powder, 10%-15% electrolytic manganese powder, 5%-8% copper powder, and the balance of auxiliary additives; the auxiliary additives include one or more of a soldering flux, an arc stabilizing agent, or a slag removing agent;

[0010] The steel strip shell is a low-carbon steel strip with a thickness of 0.4-0.6 mm and a surface roughness Ra ≤ 1.6 μm.

[0011] Preferably, the particle size of the chromium carbide particles is 50-100 μm, the particle size of the recycled slag powder is 80-180 μm, the particle size of the tungsten carbide particles is 30-50 μm, and the diameter of the carbon nanofibers is 50-100 nm.

[0012] Preferably, the recycled slag is the powder after the welding waste slag is treated by acid leaching and desiliconization, and its chromium sesquioxide content is not less than 15%, and the total content of sulfur and phosphorus impurities does not exceed 0.03%; the cobalt element content in the cobalt-based alloy powder is not less than 90%, and the vanadium element content in the ferrovanadium alloy powder is not less than 80%.

[0013] Preferably, in the mixed powder of the gradient mixing zone, the carbon nanofibers are uniformly dispersed by an ultrasonic dispersion process, the dispersion medium is anhydrous ethanol, the ultrasonic power is 200-300 W, and the dispersion time is 20-30 minutes.

[0014] Preferably, a wear-resistant flux-cored wire and its manufacturing method are characterized by including the following steps:

[0015] S1. Collect welding waste slag, crush it to a particle size less than 5 mm, remove iron filings by magnetic separation, ball mill it to 80-180 μm after acid leaching and desiliconization with a 5%-10% hydrochloric acid solution, and dry it to a moisture content not exceeding 0.5% to obtain recycled slag powder;

[0016] S2. Inner layer main wear-resistant layer batching: Weigh 30%-35% chromium carbide particles, 40%-50% recycled slag powder, 5%-8% cobalt-based alloy powder, 3%-5% carbon nanofibers, and the auxiliary additives by weight percentage, use anhydrous ethanol as the dispersion medium, ultrasonically disperse for 20-30 minutes under the condition of a power of 200-300 W, and then mix evenly; Outer layer auxiliary wear-resistant layer batching: Weigh 25%-30% tungsten carbide particles, 10%-15% ferrovanadium alloy powder, 10%-15% electrolytic manganese powder, 5%-8% copper powder, and the auxiliary additives by weight percentage, and mix evenly;

[0017] S3. Mix the powders of the inner main wear-resistant layer and the outer auxiliary wear-resistant layer according to the proportion that the proportion of the inner layer component is 50%-70% and the proportion of the outer layer component is 30%-50%, and pass through a 150-200 mesh sieve to obtain gradient mixed powder;

[0018] S4. Cold roll the low-carbon steel strip into a U-shaped groove with a groove depth of 0.4-0.6 mm. First, lay the powder of the inner main wear-resistant layer at the bottom of the groove, and the thickness accounts for 55%-60% of the total thickness of the flux-cored wire; then lay the gradient mixed powder on its surface, and the thickness accounts for 10%-15% of the total thickness of the flux-cored wire; finally, cover the powder of the outer auxiliary wear-resistant layer, and the thickness accounts for 25%-30% of the total thickness of the flux-cored wire, and vibrate and compact to make the filling rate reach 88%-92%;

[0019] S5. Close the steel strip through a double-roll mill with a rolling pressure of 5-8 MPa to form a blank welding wire; after 3-4 passes of cold drawing, the total reduction rate is 40%-50%, and the drawing speed is 8-12 m per minute to obtain a wear-resistant flux-cored wire with a diameter of 1.2-2.0 mm.

[0020] Preferably, in step S2, the surface of the tungsten carbide particles is treated by cobalt plating, and the coating thickness is 1-2 microns.

[0021] Preferably, in step S4, the vibration compaction frequency is 50-60 Hz, the compaction time of the inner main wear-resistant layer is 15-20 seconds, and the compaction time of the outer auxiliary wear-resistant layer is 10-15 seconds. Compaction is carried out in two times to ensure the density and uniformity of the flux-cored powder.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] (1) The three-layer composite structure synergistically strengthens the wear resistance: the inner main wear-resistant layer takes chromium carbide particles and recycled slag as the core to provide a high-strength wear-resistant skeleton; the outer auxiliary wear-resistant layer uses tungsten carbide particles and ferrovanadium alloy to enhance the surface impact resistance and anti-cutting ability; the intermediate gradient mixing zone reduces the interface stress concentration through the gradual transition of 50%-70% of the inner layer component and 30%-50% of the outer layer component, so that the overall bonding strength of the wear-resistant layer is increased by 30%-50%, and the wear rate is reduced by 20%-30% compared with the traditional welding wire;

[0024] (2) Industrial solid waste recycling and low cost: Recycling welding waste slag to prepare slag powder, replacing 40%-50% of the primary alloy powder, reducing the raw material cost by 15%-20%, and at the same time reducing solid waste emissions, meeting the environmental protection requirements of the "Industrial Solid Waste Comprehensive Utilization Implementation Plan"; Targeted design of auxiliary additives: the inner binder improves the formability, and the outer flux optimizes the arc stability, avoiding the process defects of traditional welding wires, with beautiful weld bead formation and good slag stripping performance;

[0025] (3) Precise process control improves forming quality: Through layered vibration compaction, precise control of the filling rate of 88%-92% is achieved. Combining with the cold drawing process, it ensures the dimensional accuracy of the welding wire and the density of the internal structure, avoiding common powder segregation or void defects in traditional welding wires. Detailed implementation manners

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Embodiment 1

[0028] I. Structural parameters of the flux-cored wire:

[0029] Inner main wear-resistant layer: accounting for 55% of the total thickness of the flux core. By weight percentage, chromium carbide particles are 30%, recycled slag powder is 40%, cobalt-based alloy powder is 8%, nano-carbon fiber is 3%, and the balance is auxiliary additives;

[0030] Gradient mixing zone: accounting for 15% of the total thickness of the flux core, with the inner layer component accounting for 50% and the outer layer component accounting for 50%. The particle size ratio of chromium carbide to tungsten carbide is 2:1, and the distribution density of nano-carbon fiber is 5×10 9 roots / cm 3 ;

[0031] Outer auxiliary wear-resistant layer: accounting for 30% of the total thickness of the flux core. By weight percentage, tungsten carbide particles are 25%, ferrovanadium alloy powder is 10%, electrolytic manganese powder is 12%, copper powder is 8%, and the balance is auxiliary additives.

[0032] II. Manufacturing method:

[0033] S1. Crush the welding waste residue, perform magnetic separation to remove iron, then perform acid leaching and desilication treatment with 5% hydrochloric acid solution for 2 hours, then carry out ball milling to make the powder particle size reach about 100 μm, and finally dry to a moisture content of less than 0.5% to obtain the recycled slag powder;

[0034] S2. Weigh each powder raw material according to the composition ratio of the inner main wear-resistant layer, add it to anhydrous ethanol, disperse it for 20 minutes under an ultrasonic power of 200 W to uniformly disperse the nano-carbon fiber. For the raw materials of the outer auxiliary wear-resistant layer, mix them in a double-cone mixer at a rotation speed of 40 rpm for 8 minutes;

[0035] S3. Mix the inner and outer layer powders according to the ratio of the gradient mixing zone, and pass through a 150-mesh sieve to ensure uniform mixing;

[0036] S4. Place the U-shaped low-carbon steel strip with a thickness of 0.3 mm and a surface roughness Ra = 1.6 μm. First, lay the inner main wear-resistant layer powder at the bottom of the groove, then vibrate and compact it at a frequency of 50 Hz for 15 seconds. Next, lay the gradient mixing zone powder, and then lay the outer auxiliary wear-resistant layer powder, and vibrate and compact it at the same frequency for 10 seconds to make the filling rate reach 88%.

[0037] S5. Through the cold drawing process, after 3 passes of drawing with a total reduction rate of 40%, a wear-resistant flux-cored wire with a diameter of 1.2 mm is obtained.

[0038] Example 2

[0039] Flux-cored wire structure parameters:

[0040] Inner main wear-resistant layer: accounting for 57% of the total thickness of the flux-cored wire. By weight percentage, chromium carbide particles are 32%, recycled slag powder is 42%, cobalt-based alloy powder is 7%, nano-carbon fiber is 3.5%, and the balance is auxiliary additives.

[0041] Gradient mixing zone: accounting for 13% of the total thickness of the flux-cored wire. The proportion of the inner layer composition is 55%, and the proportion of the outer layer composition is 45%. The particle size ratio of chromium carbide to tungsten carbide is 2.2:1, and the distribution density of nano-carbon fiber is 5.5×10 9 roots / cm 3 ;

[0042] Outer auxiliary wear-resistant layer: accounting for 30% of the total thickness of the flux-cored wire. By weight percentage, tungsten carbide particles are 26%, ferrotitanium alloy powder is 11%, electrolytic manganese powder is 11%, copper powder is 9%, and the balance is auxiliary additives.

[0043] Manufacturing method:

[0044] S1. The same waste residue treatment method as in Example 1, but the particle size of the powder after ball milling is controlled at about 120 μm.

[0045] S2. The inner layer raw materials are dispersed at an ultrasonic power of 220 W for 22 minutes, and the outer layer raw materials are mixed in a double-cone mixer at a rotation speed of 45 rpm for 9 minutes.

[0046] S3. Mix the gradient zone powder in proportion and pass through a 160-mesh sieve.

[0047] S4. The vibration compaction frequency is 52 Hz, the compaction time of the inner layer is 16 seconds, the compaction time of the outer layer is 11 seconds, and the filling rate reaches 89%.

[0048] S5. Cold drawing is carried out in 3 passes with a total reduction rate of 42% to obtain a wire with a diameter of 1.4 mm.

[0049] Example 3

[0050] Flux-cored wire structure parameters:

[0051] Inner main wear-resistant layer: accounting for 59% of the total thickness of the flux-cored wire. By weight percentage, 33% chromium carbide particles, 43% recycled slag powder, 6% cobalt-based alloy powder, 4% nano-carbon fiber, and the balance is auxiliary additive;

[0052] Gradient mixing zone: accounting for 12% of the total thickness of the flux-cored wire. The proportion of the inner layer components is 60%, and the proportion of the outer layer components is 40%. The particle size ratio of chromium carbide to tungsten carbide is 2.4:1, and the distribution density of nano-carbon fiber is 6×10 9 roots / cm 3 ;

[0053] Outer auxiliary wear-resistant layer: accounting for 29% of the total thickness of the flux-cored wire. By weight percentage, 27% tungsten carbide particles, 12% ferrovanadium alloy powder, 10% electrolytic manganese powder, 10% copper powder, and the balance is auxiliary additive.

[0054] Manufacturing method:

[0055] S1. After waste residue treatment, the ball-milled particle size is about 130 μm;

[0056] S2. The ultrasonic dispersion power of the inner layer is 240 W, and the time is 24 minutes. The rotation speed of the outer layer mixer is 50 rpm, and the mixing time is 10 minutes;

[0057] S3. The powder in the gradient zone passes through a 170-mesh sieve;

[0058] S4. The vibration compaction frequency is 54 Hz, 17 seconds for the inner layer, 12 seconds for the outer layer, and the filling rate is 90%;

[0059] S5. Cold drawing is carried out in 3 passes, the total diameter reduction rate is 44%, and the wire diameter is 1.6 mm.

[0060] Example 4

[0061] Structural parameters of the flux-cored wire:

[0062] Inner main wear-resistant layer: accounting for 61% of the total thickness of the flux-cored wire. By weight percentage, 34% chromium carbide particles, 44% recycled slag powder, 5% cobalt-based alloy powder, 4.5% nano-carbon fiber, and the balance is auxiliary additive;

[0063] Gradient mixing zone: accounting for 11% of the total thickness of the flux-cored wire. The proportion of the inner layer components is 65%, and the proportion of the outer layer components is 35%. The particle size ratio of chromium carbide to tungsten carbide is 2.6:1, and the distribution density of nano-carbon fiber is 6.5×10 9 roots / cm 3 ;

[0064] Outer auxiliary wear-resistant layer: accounting for 28% of the total thickness of the flux-cored wire. By weight percentage, 28% tungsten carbide particles, 13% ferrovanadium alloy powder, 9% electrolytic manganese powder, 11% copper powder, and the balance is auxiliary additive.

[0065] Manufacturing method:

[0066] S1. The particle size of the powder after ball milling is about 140 μm;

[0067] S2. The ultrasonic dispersion power of the inner layer is 260 W, the time is 26 minutes, the rotation speed of the outer mixer is 55 rpm, and the mixing time is 11 minutes;

[0068] S3. The powder in the gradient zone passes through a 180-mesh sieve;

[0069] S4. The vibration compaction frequency is 56 Hz, 18 seconds for the inner layer, 13 seconds for the outer layer, and the filling rate is 91%;

[0070] S5. Cold drawing is carried out in 3 passes, the total diameter reduction rate is 46%, and the wire diameter is 1.8 mm.

[0071] Example 5

[0072] Structural parameters of the flux-cored wire:

[0073] Inner main wear-resistant layer: accounting for 63% of the total thickness of the flux core. By weight percentage, chromium carbide particles are 35%, recycled slag powder is 45%, cobalt-based alloy powder is 4%, nano-carbon fiber is 5%, and the balance is auxiliary additives;

[0074] Gradient mixing zone: accounting for 10% of the total thickness of the flux core, the proportion of the inner layer component is 70%, the proportion of the outer layer component is 30%, the particle size ratio of chromium carbide to tungsten carbide is 2.8:1, and the nano-carbon fiber distribution density is 7×10 9 roots / cm 3 ;

[0075] Outer auxiliary wear-resistant layer: accounting for 27% of the total thickness of the flux core. By weight percentage, tungsten carbide particles are 29%, ferrovanadium alloy powder is 14%, electrolytic manganese powder is 8%, copper powder is 12%, and the balance is auxiliary additives.

[0076] Manufacturing method:

[0077] S1. The particle size of the powder after ball milling is about 150 μm;

[0078] S2. The ultrasonic dispersion power of the inner layer is 280 W, the time is 28 minutes, the rotation speed of the outer mixer is 60 rpm, and the mixing time is 12 minutes;

[0079] S3. The powder in the gradient zone passes through a 190-mesh sieve;

[0080] S4. The vibration compaction frequency is 58 Hz, 19 seconds for the inner layer, 14 seconds for the outer layer, and the filling rate is 92%;

[0081] S5. Cold drawing is carried out in 3 passes, the total diameter reduction rate is 48%, and the wire diameter is 2.0 mm.

[0082] Example 6

[0083] Structural parameters of the flux-cored wire:

[0084] Inner main wear-resistant layer: accounting for 56% of the total thickness of the flux core. By weight percentage, chromium carbide particles are 31%, recycled slag powder is 41%, cobalt-based alloy powder is 7.5%, nano-carbon fiber is 3.2%, and the balance is auxiliary additives;

[0085] Gradient mixing zone: accounting for 14% of the total thickness of the flux core. The proportion of the inner layer component is 52%, and the proportion of the outer layer component is 48%. The particle size ratio of chromium carbide to tungsten carbide is 2.1:1, and the distribution density of nano-carbon fiber is 5.2×10 9 roots / cm 3 ;

[0086] Outer auxiliary wear-resistant layer: accounting for 30% of the total thickness of the flux core. By weight percentage, tungsten carbide particles are 25.5%, ferrovanadium alloy powder is 10.5%, electrolytic manganese powder is 11.5%, copper powder is 8.5%, and the balance is auxiliary additives.

[0087] Manufacturing method:

[0088] S1. The particle size of the powder after ball milling is about 110μm;

[0089] S2. The ultrasonic dispersion power of the inner layer is 210W, and the time is 21 minutes. The rotation speed of the outer layer mixer is 42rpm, and the mixing time is 8.5 minutes;

[0090] S3. The powder in the gradient zone passes through a 155-mesh sieve;

[0091] S4. The vibration compaction frequency is 51Hz, 15.5 seconds for the inner layer, 10.5 seconds for the outer layer, and the filling rate is 88.5%;

[0092] S5. Cold drawing is carried out in 3 passes, the total diameter reduction rate is 41%, and the wire diameter is 1.3mm.

[0093] Example 7

[0094] Structural parameters of the flux-cored wire:

[0095] Inner main wear-resistant layer: accounting for 60% of the total thickness of the flux core. By weight percentage, chromium carbide particles are 33.5%, recycled slag powder is 43.5%, cobalt-based alloy powder is 5.5%, nano-carbon fiber is 4.2%, and the balance is auxiliary additives;

[0096] Gradient mixing zone: accounting for 12% of the total thickness of the flux core. The proportion of the inner layer component is 62%, and the proportion of the outer layer component is 38%. The particle size ratio of chromium carbide to tungsten carbide is 2.5:1, and the distribution density of nano-carbon fiber is 6.2×10 9 roots / cm 3 ;

[0097] Outer auxiliary wear-resistant layer: accounting for 28% of the total thickness of the flux cored wire. By weight percentage, tungsten carbide particles are 27.5%, ferrovanadium alloy powder is 12.5%, electrolytic manganese powder is 9.5%, copper powder is 10.5%, and the balance is auxiliary additive.

[0098] Manufacturing method:

[0099] S1. The particle size of the powder after ball milling is about 135μm;

[0100] S2. The ultrasonic dispersion power of the inner layer is 250W, and the time is 25 minutes. The rotation speed of the outer layer mixer is 52rpm, and the mixing time is 10.5 minutes;

[0101] S3. The powder in the gradient zone passes through a 175-mesh sieve;

[0102] S4. The vibration compaction frequency is 55Hz, 17.5 seconds for the inner layer and 12.5 seconds for the outer layer, and the filling rate is 90.5%;

[0103] S5. Cold drawing is carried out in 3 passes, the total diameter reduction rate is 45%, and the wire diameter is 1.7mm.

[0104] Example 8

[0105] Structural parameters of the flux cored wire:

[0106] Inner main wear-resistant layer: accounting for 62% of the total thickness of the flux cored wire. By weight percentage, chromium carbide particles are 34.5%, recycled slag powder is 44.5%, cobalt-based alloy powder is 4.5%, and nano-carbon fiber is 4.8%, and the balance is auxiliary additive;

[0107] Gradient mixing zone: accounting for 11% of the total thickness of the flux cored wire, the proportion of the inner layer component is 67%, the proportion of the outer layer component is 33%, the particle size ratio of chromium carbide to tungsten carbide is 2.7:1, and the distribution density of nano-carbon fiber is 6.8×10 9 roots / cm 3 ;

[0108] Outer auxiliary wear-resistant layer: accounting for 27% of the total thickness of the flux cored wire. By weight percentage, tungsten carbide particles are 28.5%, ferrovanadium alloy powder is 13.5%, electrolytic manganese powder is 8.5%, copper powder is 11.5%, and the balance is auxiliary additive.

[0109] Manufacturing method:

[0110] S1. The particle size of the powder after ball milling is about 145μm;

[0111] S2. The ultrasonic dispersion power of the inner layer is 270W, and the time is 27 minutes. The rotation speed of the outer layer mixer is 57rpm, and the mixing time is 11.5 minutes;

[0112] S3. The powder in the gradient zone passes through a 185-mesh sieve;

[0113] S4. The vibration compaction frequency is 57 Hz, 18.5 seconds for the inner layer, 13.5 seconds for the outer layer, and the filling rate is 91.5%.

[0114] S5. Cold drawing is carried out in 3 passes, the total diameter reduction rate is 47%, and the wire diameter is 1.9 mm.

[0115] Comparative Example 1

[0116] Structural parameters of the flux-cored wire:

[0117] Adopt the traditional single-layer structure, and the flux core is all 60% chromium carbide particles, 20% cobalt-based alloy powder, and the balance is auxiliary additives.

[0118] Manufacturing method:

[0119] Mix the above raw materials in a double-cone mixer at a speed of 50 rpm for 10 minutes, then fill them into a U-shaped low-carbon steel strip with a thickness of 0.4 mm, and through the cold drawing process, after 3 passes of drawing, the total diameter reduction rate is 45%, and a wire with a diameter of 1.6 mm is obtained.

[0120] Comparative Example 2

[0121] Structural parameters of the flux-cored wire:

[0122] Adopt a two-layer structure. The inner layer is 70% chromium carbide particles, 20% cobalt-based alloy powder, and the balance is auxiliary additives, accounting for 70% of the total thickness of the flux core; the outer layer is 80% tungsten carbide particles, 10% ferrovanadium alloy powder, and the balance is auxiliary additives, accounting for 30% of the total thickness of the flux core.

[0123] Manufacturing method:

[0124] The raw materials of the inner layer and the outer layer are mixed separately in a double-cone mixer, then filled into the U-shaped low-carbon steel strip in sequence, and after vibration compaction, cold drawing is carried out. After 3 passes of drawing, the total diameter reduction rate is 45%, and a wire with a diameter of 1.6 mm is obtained.

[0125] Performance test

[0126] I. Unify the test substrate and object

[0127] 1. Substrate selection:

[0128] For the surfacing tests of all examples and comparative examples, Q235 carbon steel is used as the substrate, with the dimensions uniformly 100 mm × 50 mm × 10 mm. The surface is polished with sandpaper, the surface roughness Ra ≤ 3.2 μm, and the oil stain is removed to ensure the same surface state of the substrate;

[0129] The surfacing layer thickness is uniformly controlled at 3 mm, adjusted by the welding current and speed, and the surfacing area of each specimen is in the range of 50 mm × 50 mm in the center to avoid the influence of edge effect on the test results.

[0130] 2. Specimen preparation:

[0131] Before surfacing, all welding wires were dried at 150°C for 1 hour to remove moisture. The Lincoln DC-400 arc welding power source was uniformly used for the welding equipment, and the welding parameters were fixed as follows:

[0132] Current: 180 ± 5 A, corresponding to the standard process parameters for welding wire diameters of 1.2 - 2.0 mm;

[0133] Voltage: 24 ± 1 V, welding speed: 250 mm / min, shielding gas: 80% Ar + 20% CO2, flow rate 15 L / min;

[0134] After surfacing, the specimens were all stress-relieved annealed, heated to 550°C and held for 2 hours, and cooled in the furnace to eliminate the influence of welding thermal stress on the performance.

[0135] II. Testing standards and methods

[0136] 1. Wear loss testing:

[0137] Standard: GB / T12988 - 2009 "Test Method for Wear Resistance of Inorganic Floor Materials"

[0138] Each specimen was subjected to 3 parallel tests on an abrasive wear testing machine. The rotation direction of the grinding wheel was perpendicular to the surface of the surfacing layer to ensure consistent wear paths;

[0139] New quartz sand, 2 kg, was replaced before each test to avoid the influence of abrasive fatigue on the test accuracy. The wear loss was taken as the average of 3 times, and the error was controlled within ±3%.

[0140] 2. Bonding strength testing:

[0141] Standard: GB / T8642 - 2002 "Determination of Tensile Bonding Strength of Thermal Spraying"

[0142] The "cylindrical tensile method" was adopted: a Φ10 mm cylindrical specimen was machined at the center of the surfacing layer, and the two ends were welded to the substrate and the tensile fixture respectively to ensure that the stress direction was perpendicular to the surfacing layer interface;

[0143] The maximum fracture load was recorded during the tensile process. Bonding strength = fracture load / specimen cross-sectional area. If the fracture occurred in the substrate rather than at the interface, the bonding strength was determined to be ≥ 55 MPa of the substrate strength and was regarded as qualified.

[0144] 3. Impact absorption energy testing:

[0145] Standard: GB / T229 - 2020 "Metallic Materials - Charpy Pendulum Impact Test Method"

[0146] Three standard impact specimens of 10mm×10mm×55mm are processed for each surfacing layer, with the notch axis perpendicular to the surfacing layer surface, ensuring that the impact energy acts on the interlayer interface area;

[0147] The impact test is carried out at room temperature, and the result is the average value of 3 tests, and the abnormal data with a deviation exceeding 10% is discarded.

[0148] 4. Arc stability:

[0149] Standard: GB / T19867.1-2017 "Arc Welding Welding Procedure Specification Part 1: Steel"

[0150] By observing whether the arc burns stably, whether there is arc interruption or spatter during the welding process, referring to the arc stability level classification in ISO15614-1 "Welding Procedure Specifications and Qualification for Metallic Materials", Grade A: no arc interruption; Grade B: occasional arc interruption; Grade C: frequent arc interruption.

[0151] 5. Slag detachment rate:

[0152] Standard: JB / T7949-1999 "Weld Appearance Dimensions of Steel Structures"

[0153] After welding, it is naturally cooled, and the slag is removed by the knocking method. Calculate the percentage of the residual slag in the surface area of the surfacing layer. The slag detachment rate = (1 - residual slag area / total surfacing layer area) × 100%.

[0154] III. Comparison of Performance Test Results

[0155] Table 1 Comparison of Performance Test Results between Examples and Comparative Examples

[0156]

[0157]

[0158] Summary of test results:

[0159] 1. Significantly superior wear resistance: The wear amount of all examples is lower than the excellent grade of the national standard. Among them, the wear amount of Example 5 is reduced by 56% compared with Comparative Example 1, verifying the synergistic wear resistance effect between the inner layer and the outer layer in the three-layer structure, and the inhibitory effect of nano-carbon fibers on crack propagation.

[0160] 2. Greatly improved bonding strength: The bonding strength of the examples is all ≥78MPa, significantly higher than 55MPa of Comparative Example 1 and 68MPa of Comparative Example 2. The core reason is that the gradual transition of the composition in the gradient mixing zone reduces the interface stress concentration, which is 25%-40% higher than the traditional two-layer structure.

[0161] 3. Excellent impact resistance and process stability: The impact absorption work is all ≥ 45 J, while that of Comparative Example 1 is only 32 J, indicating that the distribution density of nano-carbon fibers ≥ 5×10 9 roots / cm 3 , effectively enhancing the toughness of the surfacing layer; the arc stability all reaches Class A, while that of Comparative Example 1 is Class C with arc interruption, and the slag detachment rate ≥ 94%, while that of Comparative Example 1 is only 75%. Thanks to the optimization of the welding process by the outer auxiliary flux and arc stabilizing agent.

[0162] Through the comparative tests of the examples and comparative examples, the three-layer structured wear-resistant flux cored wire of the present invention is significantly superior to the traditional wire in the four core indexes of wear resistance, bonding strength, impact resistance and process stability, fully meeting the application requirements of high-load wear-resistant scenarios in heavy industry, and proving the feasibility and innovation of the technical solutions in the claims.

[0163] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions in the specification are only the preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A wear-resistant flux-cored wire, comprising a steel strip shell and a flux core filled in the steel strip, characterized in that: The flux core is sequentially divided into an inner main wear-resistant layer, a gradient mixing zone, and an outer auxiliary wear-resistant layer from the inside out in the cross-sectional direction; The inner main wear-resistant layer accounts for 55%-60% of the total thickness of the flux core and, by weight percentage, includes: 30%-35% chromium carbide particles, 40%-50% recycled slag powder, 5%-8% cobalt-based alloy powder, 3%-5% nanofiber carbon, and the balance of auxiliary additives; the auxiliary additives include one or more of a binder, a slag-forming agent, or a deoxidizer; The gradient mixing zone accounts for 10%-15% of the total thickness of the flux cored wire, and contains a mixed powder composed of 50%-70% of the inner main wear-resistant layer and 30%-50% of the outer auxiliary wear-resistant layer. The particle size ratio of chromium carbide particles to tungsten carbide particles in the mixed powder is 2-3:1, and the distribution density of nano-carbon fibers in the mixed powder is not less than 5×10 5 roots per cubic centimeter; The outer auxiliary wear-resistant layer accounts for 25%-30% of the total thickness of the flux core and, by weight percentage, includes: 25%-30% tungsten carbide particles, 10%-15% ferroniobium alloy powder, 10%-15% electrolytic manganese powder, 5%-8% copper powder, and the balance of auxiliary additives; the auxiliary additives include one or more of a soldering flux, an arc stabilizing agent, or a slag removing agent; The steel strip shell is a low-carbon steel strip with a thickness of 0.4-0.6 mm and a surface roughness Ra ≤ 1.6 μm.

2. The wear-resistant flux-cored wire according to claim 1, wherein The chromium carbide particles have a particle size of 50-100 μm, the recycled slag powder has a particle size of 80-180 μm, the tungsten carbide particles have a particle size of 30-50 μm, and the nanofiber carbon has a diameter of 50-100 nm.

3. The wear-resistant flux-cored wire according to claim 1, characterized in that The recycled slag is the powder after acid leaching and desiliconization treatment of welding waste slag, and its chromium sesquioxide content is not less than 15%, and the total content of sulfur and phosphorus impurities does not exceed 0.03%; the cobalt element content in the cobalt-based alloy powder is not less than 90%, and the vanadium element content in the ferroniobium alloy powder is not less than 80%.

4. A wear-resistant flux-cored wire according to claim 1, characterized in that, In the mixed powder of the gradient mixing zone, the nanofiber carbon is uniformly dispersed by an ultrasonic dispersion process, the dispersion medium is anhydrous ethanol, the ultrasonic power is 200-300 W, and the dispersion time is 20-30 minutes.

5. A wear-resistant flux-cored wire and a manufacturing method thereof according to any one of claims 1-4, characterized in that It includes the following steps: S1. Collect welding waste slag, crush it to a particle size less than 5 mm, remove iron filings by magnetic separation, ball mill it to 80-180 μm after acid leaching and desiliconization with a 5%-10% hydrochloric acid solution, and dry it to a moisture content not exceeding 0.5% to obtain recycled slag powder; S2. Inner main wear-resistant layer batching: Weigh 30%-35% chromium carbide particles, 40%-50% recycled slag powder, 5%-8% cobalt-based alloy powder, 3%-5% nanofiber carbon, and the auxiliary additives by weight percentage, use anhydrous ethanol as the dispersion medium, ultrasonically disperse for 20-30 minutes under the condition of a power of 200-300 W, and then mix evenly; Outer auxiliary wear-resistant layer batching: Weigh 25%-30% tungsten carbide particles, 10%-15% ferroniobium alloy powder, 10%-15% electrolytic manganese powder, 5%-8% copper powder, and the auxiliary additives by weight percentage, and mix evenly; S3. Mix the powders of the inner main wear-resistant layer and the outer auxiliary wear-resistant layer according to the ratio of the inner layer component accounting for 50%-70% and the outer layer component accounting for 30%-50%, and pass through a 150-200 mesh sieve to obtain gradient mixed powder; S4. Cold roll the low-carbon steel strip into a U-shaped groove with a groove depth of 0.4 - 0.6 mm. First, lay the inner main wear-resistant layer powder at the bottom of the groove, with a thickness accounting for 55% - 60% of the total thickness of the flux-cored wire; then lay the gradient mixed powder on its surface, with a thickness accounting for 10% - 15% of the total thickness of the flux-cored wire; finally, cover it with the outer auxiliary wear-resistant layer powder, with a thickness accounting for 25% - 30% of the total thickness of the flux-cored wire, and vibrate and compact to make the filling rate reach 88% - 92%; S5. Close the steel strip through a two-roll mill with a rolling pressure of 5 - 8 MPa to form a blank welding wire; after 3 - 4 passes of cold drawing with a total reduction rate of 40% - 50% and a drawing speed of 8 - 12 m per minute, obtain a wear-resistant flux-cored wire with a diameter of 1.2 - 2.0 mm.

6. The manufacturing method according to claim 5, characterized in that, In the step S2, the surface of the tungsten carbide particles is treated by cobalt plating with a coating thickness of 1 - 2 μm.

7. The manufacturing method according to claim 5, characterized in that, In the step S4, the vibration compaction frequency is 50 - 60 Hz, the compaction time of the inner main wear-resistant layer is 15 - 20 seconds, and the compaction time of the outer auxiliary wear-resistant layer is 10 - 15 seconds. Compaction is carried out in two times to ensure the density and uniformity of the flux-cored wire powder.

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