Metal powder material for repairing high-speed train wheels as well as preparation method and use method of metal powder material

Abstract

The invention relates to a metal powder material for repairing wheels of a high-speed train, which comprises a basic metal powder part and a nano oxide adding part, and the nano oxide adding part accounts for 1.0-1.6% of the total mass of the basic metal powder part. And the nano oxide adding part is obtained by carrying out ball milling treatment on zirconium oxide nano powder and yttrium oxide nano powder. A nano oxide material is added into a metal powder material, and a magnetic field and intermittent ultrasonic oscillation are applied in the laser cladding process, so that uniform dispersion of metal particles is effectively promoted, formation of defects is reduced, the quality and performance of a cladding layer are improved, it is ensured that a repaired position can be perfectly fused with a wheel, and the repairing quality is improved. Normal safety performance requirements are met, wheel replacement is avoided or reduced, and maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and particularly relates to a metal powder material for repairing high-speed train wheels, a preparation method thereof, and a usage method thereof. Background Art

[0002] Wheels and rails are important components required for train operation. With the development of trains in China towards high speed and heavy load, the damage problems of train wheels and rails have become more prominent. Among them, the peeling and chipping of the rail and the wheel tread are damage forms that seriously affect the safe operation of trains. After the wheel and rail tread are damaged, the common practice is to turn and grind the wheels. When the peeling depth is large, resulting in too many turning or grinding times, the wheels and rails will be scrapped due to reaching the size limit, greatly affecting the service life of the wheels and rails. This not only increases the operation cost but also causes a great waste of resources.

[0003] The damaged part can be repaired by laser cladding to restore its original size and performance. For example, Chinese Patent CN107620060A discloses a metal powder for laser cladding to repair 160CrNiMo semi-steel rolls. The mass fraction of the chemical composition of the metal powder is: 0.05 - 0.30% C, 0.20 - 1.80% Si, 0.10 - 1.60% Mn, 10.0 - 20.0% Cr, 0.30 - 3.55% Mo, 0.50 - 3.55% Ni, P ≤ 0.030%, S ≤ 0.030%, 0.20 - 1.80% B. The particle size distribution of the powder is: 50 - 200μm, and the fluidity is: 12 - 25s / 50g. When this metal powder is used for laser cladding repair, although cracks, holes and other defects in the wheels can be repaired, during the cladding process, due to the different melting points of each metal element, and the uneven particle size distribution and irregular shape, part of the powder is difficult to be completely melted, resulting in problems such as lack of fusion defects and increased porosity, and the repair effect is not very ideal, which has a certain impact on the operation of the wheels. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the present invention provides a metal powder material for repairing high-speed train wheels, a preparation method thereof, and a usage method thereof. By designing a suitable base metal composition and ratio, and adding an appropriate amount of nano-oxide powder, the obtained metal powder material has good dispersibility and reduced friction between particles, which helps to reduce the formation of later hole defects; and enables all the metal powder to be fully melted, and after rapid solidification, a surface coating with extremely low dilution and metallurgical bonding with the base material is formed, thereby ensuring the quality and performance of the cladding layer.

[0005] To achieve the above object, a first aspect of the present invention provides a metal powder material for repairing high-speed train wheels. The metal powder material includes a base metal powder portion and a nano-oxide additive portion. The nano-oxide additive portion is 1.0 - 1.6% of the total mass of the base metal powder portion. Among them,

[0006] The components and mass percentages of the base metal powder portion are: C ≤ 0.56%, Si ≤ 0.40%, Mn ≤ 0.80%, Cr 10.0 - 20.0%, Mo 0.30 - 1.25%, P ≤ 0.020%, S ≤ 0.015%, B 0.20 - 1.80%, Ni 5.0 - 7.0%, Cu 2.0 - 3.0%, Nb 0.02 - 0.05%, Re 1.2 - 1.8%, and the balance is Fe and unavoidable impurities;

[0007] The nano-oxide additive portion is composed of zirconia nanopowder and yttria nanopowder, and the mass ratio of zirconia nanopowder to yttria nanopowder is 1:(1.0 - 1.6).

[0008] Furthermore, the nano-oxide additive portion is obtained by ball-milling and mixing zirconia nanopowder and yttria nanopowder.

[0009] Furthermore, the base metal powder portion is an alloy powder of the components included.

[0010] Furthermore, the particle size of the base metal powder portion is 15 - 100 μm, preferably 30 - 60 μm; the zirconia nanopowder is flaky, the yttria nanopowder is rod-shaped, and the particle sizes of the zirconia nanopowder and the yttria nanopowder are 20 - 80 nm, preferably 30 - 50 nm. The particle sizes of the above nano-powders refer to the particle sizes when equivalent to the volume of spherical particles.

[0011] A second aspect of the present invention provides a preparation method of the above metal powder material for repairing high-speed train wheels. The preparation method includes the following steps for preparing the nano-oxide additive portion:

[0012] (1) Add zirconium oxychloride to deionized water to dissolve it, and then drop in phosphoric acid solution. During the dropping process, mechanical stirring is accompanied to form a precursor sol. Then transfer the obtained precursor sol to a reaction kettle and carry out hydrothermal reaction for 24 - 30 h. After the reaction ends, wash the obtained product by centrifugation and dry it at 70 - 80 °C to obtain flaky zirconia nanopowder;

[0013] (2) Dissolve yttrium nitrate in deionized water to obtain a yttrium nitrate solution. Adjust the pH value of the saturated sodium hydroxide solution to 12 - 13, and then perform forward titration. Titrate the yttrium nitrate solution into the above-mentioned sodium hydroxide solution at an average speed of 2.0 - 2.6 mL / min to obtain a precipitate precursor. Transfer the precipitate precursor into a reaction kettle, carry out hydrothermal reaction for 24 - 30 h. After the reaction, filter, wash with deionized water and absolute ethanol, and vacuum dry at 80 - 90 °C for 4 - 6 h. Place the dried powder in a calcination furnace and calcine for 5 - 8 h, and then naturally cool to room temperature to obtain rod-shaped yttrium oxide nano-powder;

[0014] (3) Mix zirconium oxide nano-powder and yttrium oxide nano-powder evenly to obtain an abrasive. Then mix the abrasive with water and pour it into a ball mill. Use zirconia balls as the grinding medium, and ball mill for 1 - 2 h according to a ball-to-material ratio of (2 - 3):1. After the treatment is completed, centrifuge and wash the product and then dry it to obtain the nano-oxide addition part.

[0015] As a preferred embodiment, in step (1), the ratio of zirconium oxychloride, deionized water, and phosphoric acid solution is (1.5 - 2.3) g:(5 - 10) mL:(15 - 20) mL, and the phosphoric acid solution is an aqueous solution with a concentration of 3.0 - 3.4 mol / L; the rotation speed of the mechanical stirring is 500 - 800 r / min; the temperature of the hydrothermal reaction is 200 - 210 °C.

[0016] As a preferred embodiment, in step (2), the concentration of the yttrium nitrate solution is 0.2 - 0.5 mol / L; the temperature of the hydrothermal reaction is 180 - 186 °C; the temperature of the calcination is 620 - 650 °C.

[0017] As a preferred embodiment, in step (3), the mass ratio of the abrasive to water is 1:(0.9 - 1.1).

[0018] Furthermore, the preparation method further includes preparing the base metal powder part and mixing the base metal powder part and the nano-oxide addition part evenly.

[0019] The base metal powder part can be prepared by alloying the raw material components, vacuum hot melting, atomizing and spraying powder, and then performing particle size screening, or other methods for preparing metal powder materials in the prior art, such as mechanical alloying method, plasma rotating electrode atomization method, spray deposition method, etc.

[0020] In one embodiment, the base metal powder portion is obtained by forming elemental metal powder from one or more elemental components in the base metal powder portion and then mixing it with alloy powder of the remaining elemental components. For example, Cr, Ni, Cu, and / or Fe can be formed into elemental metal powder and then mixed with alloy powder of the remaining elemental components to obtain the base metal powder portion, which is advantageous when certain process conditions need to be adjusted, such as adjusting the alloy melting point.

[0021] The third aspect of the present invention provides a method of using the metal powder material for repairing high-speed train wheels, which is used for laser cladding repair of high-speed train wheels and includes the following steps:

[0022] S1. Grind the area to be repaired on the wheel to remove the surface oxide layer, stains, and surface fatigue cracks, wipe it with alcohol, and then perform penetrant flaw detection to confirm that there are no crack and hole defects in the area to be repaired; measure the length, width, and depth of the area to be repaired, and write a process program for laser cladding based on the obtained data;

[0023] S2. Under the action of a magnetic field, apply intermittent ultrasonic vibration, and use a fiber laser to perform laser cladding on the area to be repaired. Among them, the above-mentioned metal powder material for repairing high-speed train wheels is used as the metal powder for laser cladding, and argon with a purity greater than 99.9% is used as the metal powder carrier gas and molten pool protection gas during the cladding process;

[0024] S3. After the laser cladding is completed, perform penetrant flaw detection on the area treated by laser cladding again to determine that no crack and hole defects are shown; grind the laser cladding allowance to restore the size and wheel shape of the wheel, and make the surface quality of the repaired area of the wheel meet the use requirements; finally, use ultrasonic flaw detection method to detect the repaired area of the wheel to ensure that there are no internal defects affecting the use safety in the repaired wheel.

[0025] As a preferred embodiment, in step S2, the intensity of the magnetic field is 1.0 - 1.2T; the power of the intermittent ultrasonic vibration is 200 - 300W, the ultrasonic vibration device generating ultrasonic waves is non-contact with the wheel, and the ultrasonic vibration device stops operating for 20 - 30s after continuously operating for 1 - 2min and then resumes operation, and this cycle repeats.

[0026] As a preferred embodiment, in step S2, the diameter of the focused laser spot for laser cladding is 2 - 10mm, the scanning rate is set to 10 - 20mm / s; the laser power range used is 1500 - 3000W, and the laser energy is evenly distributed in the spot plane.

[0027] As a preferred embodiment, in step S2, the flow rate of the carrier gas for the metal powder is 5 - 10 L / min, the flow rate of the molten pool protective gas is 10 - 20 L / min, and the metal powder feeding speed is set to 10 - 25 g / min.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. In the present invention, zirconium oxychloride and phosphoric acid are used as the zirconium source and phosphorus source, and nano - sheet - shaped zirconia nano - powder is obtained through a hydrothermal reaction; at the same time, yttrium nitrate is used as a raw material, and a yttrium oxide precursor is synthesized by a hydrothermal method under alkaline conditions, and then nano - rod - shaped yttrium oxide nano - powder can be obtained through high - temperature calcination; then, zirconia balls are used as the ball - milling medium, and the zirconia nano - powder and yttrium oxide nano - powder are wet - ball - milled. Under the action of ball - milling, the edges and corners of the nano - sheet - shaped zirconia nano - powder and nano - rod - shaped yttrium oxide nano - powder can be polished, making the edges and corners more rounded, and some irregular protrusions on the surface of the nano - sheets and nano - rods can be polished off, making the surface smoother and flatter, which helps to form better relative sliding and relative rolling and reduce the frictional resistance between particles.

[0030] 2. In the present invention, during the laser cladding of wheel defects, since the metal powder material is composed of multiple metal elements with different melting points, during the cladding process, some low - melting - point metal elements first melt into a liquid state, while the high - melting - point elements remain solid. At this time, the liquid metal has a large viscous effect, and the surface of the metal particles is rough with a large frictional force, resulting in it being difficult for the solid - state metal particles to be evenly dispersed. Therefore, it is necessary to reduce the viscous effect so that the metal particles can be dispersed. In the present invention, the prepared nano - material is added. The sheet - shaped zirconia nano - powder in the nano - material has a high melting point and can adhere to the surface of the metal particles in the early stage to form a physical adsorption lubricating film with low shear force, separating the originally rough friction surface of the metal particles, making the friction between particles become the relative sliding between nano - sheet layers or between the nano - sheet and the particle surface, thereby reducing the frictional resistance suffered by the metal particles during movement, which is beneficial to uniform dispersion and helps to reduce the formation of later hole defects; at the same time, the high - melting - point rod - shaped yttrium oxide nano - powder can act as a rolling roller, causing rolling friction between metal particles, further reducing the frictional resistance, enabling the metal particles to be highly dispersed and evenly distributed, and all metal components can be fully melted and simultaneously melted with a thin layer on the wheel surface, so that a surface coating with extremely low dilution and metallurgical bonding with the substrate material is formed after rapid solidification, ensuring the quality and performance of the cladding layer.

[0031] 3. In the present invention, during the laser cladding process, the Lorentz force induced by applying a magnetic field inhibits the fluid motion, thereby reducing the formation of pores. Moreover, by applying intermittent ultrasonic vibrations in a non-contact manner, the migration movement of metal powder is slow and gradual under the action of ultrasound. This not only promotes the migration movement of metal powder but also avoids the overflow of molten metal caused by violent movement, enabling the molten metal to fully fill the defects in the wheel.

[0032] 4. In the present invention, a metal powder material is formed by mixing base metal powder and nanomaterials. This material has high strength, high toughness, and hardness. During the laser cladding process, under the application of a magnetic field and intermittent ultrasonic oscillations, the uniform dispersion of metal particles is effectively promoted, enabling all metal powders to be fully melted, thereby reducing the formation of defects, improving the quality and performance of the cladding layer, ensuring that the repaired position can be perfectly integrated with the wheel, meeting the normal safety performance requirements, avoiding or reducing wheel replacement, and thus reducing the maintenance cost. Detailed implementation mode

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] Embodiment 1

[0035] A metal powder material for repairing high-speed train wheels, the metal powder material includes a base metal powder part and a nano-oxide addition part. The nano-oxide addition part is 1.0% of the total mass of the base metal powder part. Among them,

[0036] The composition and mass percentage of the base metal powder part are: C ≤ 0.56%, Si ≤ 0.40%, Mn ≤ 0.80%, Cr 10.0%, Mo 0.30%, P ≤ 0.020%, S ≤ 0.015%, B 0.20%, Ni 5.0%, Cu 2.0%, Nb 0.02%, Re 1.2%, and the balance is Fe and unavoidable impurities;

[0037] The nano-oxide addition part is composed of plate-shaped zirconia nano-powder and rod-shaped yttrium oxide nano-powder in a mass ratio of 1:1 and obtained after ball milling treatment.

[0038] The preparation method of the nano-oxide addition material is as follows:

[0039] 1) Add 1.5 g of zirconium oxychloride to 5 mL of deionized water to dissolve it, and then dropwise add 15 mL of phosphoric acid solution with a concentration of 3.0 mol / L. During the dropping process, mechanically stir at 500 r / min to form a precursor sol. Then transfer the precursor sol to a reaction kettle and carry out a hydrothermal reaction at 200 °C for 24 h. After the reaction is completed, wash the obtained product by centrifugation and dry it at 70 °C to obtain nanosheet zirconia nanopowder;

[0040] 2) Dissolve yttrium nitrate in deionized water to make a yttrium nitrate solution with a concentration of 0.2 mol / L. Adjust the pH value to 12 with saturated sodium hydroxide solution, and then use forward titration to titrate the yttrium nitrate solution into the sodium hydroxide solution at an average speed of 2.0 mL / min to obtain a precipitate precursor. Then transfer the precipitate precursor to a reaction kettle and carry out a hydrothermal reaction at 180 °C for 24 h. After the reaction, filter it, repeatedly wash it with deionized water and absolute ethanol, and dry it under vacuum at 80 °C for 4 h. Place the dried powder in a calcination furnace and calcine it at 620 °C for 5 h, and naturally cool it to room temperature to obtain rod-shaped yttrium oxide nanopowder;

[0041] 3) Mix the zirconia nanopowder and yttrium oxide nanopowder evenly according to a mass ratio of 1:1 to obtain an abrasive. Then mix the abrasive and water according to a mass ratio of 1:0.9 and pour them into a ball mill. Use zirconia balls as the grinding medium and ball mill at a ball-to-material ratio of 2:1 for 1 h. After the treatment is completed, wash the product by centrifugation and dry it to obtain the required nano-oxide additive part.

[0042] Obtain the base metal powder part by gas atomization method, and mix the base metal powder part and the nano-oxide additive part evenly to obtain the metal powder material.

[0043] The usage method of using this metal powder material for wheel repair includes the following steps:

[0044] S1. Manually grind the defective position of the wheel to be repaired to remove the surface oxide layer, stains and surface fatigue cracks, wipe it with alcohol, and then carry out penetrant flaw detection to confirm that there are no residual defects such as cracks and holes in the area to be repaired that are not conducive to laser cladding repair. Then measure the length, width and depth of the area to be repaired, and write the laser cladding process program according to the obtained data;

[0045] S2. Under the action of a 1.0T magnetic field, intermittent ultrasonic vibration is applied, and laser cladding is carried out using a fiber laser. The diameter of the focused laser spot for laser cladding is 2 mm, the scanning rate is set at 10 mm / s, the laser power range is 1500 W, and the laser energy is evenly distributed in the spot plane; during the cladding process, argon with a purity greater than 99.9% is used as the carrier gas for the metal powder and the shielding gas for the molten pool. The flow rate of the carrier gas for the metal powder is 5 L / min, the flow rate of the shielding gas for the molten pool is 10 L / min, and the feeding speed of the metal powder is set at 10 g / min;

[0046] This intermittent ultrasonic vibration has a power of 200 W. The ultrasonic vibration device that generates ultrasonic waves is non-contact with the wheel, and the ultrasonic vibration device stops working for 20 s after every 1 min of continuous operation and then acts again, repeating this cycle;

[0047] S3. After the laser cladding is completed, the repaired area of the wheel is subjected to penetrant flaw detection to determine that no cracks and hole defects are shown. A portable grinding machine is used to grind the laser cladding allowance in the repaired area of the wheel to restore the size and shape of the wheel and make the surface quality of the defect repair area of the wheel meet the use requirements. Finally, an ultrasonic flaw detection method is used to detect the defect repair area to ensure that there are no internal defects in the repaired wheel that affect the use safety.

[0048] Example 2

[0049] A metal powder material for repairing high-speed train wheels, the metal powder material includes a basic metal powder part and a nano-oxide addition part. The nano-oxide addition part is 1.2% of the total mass of the basic metal powder part. Among them,

[0050] The composition and mass percentage of the basic metal powder part are: C≤0.56%, Si≤0.40%, Mn≤0.80%, Cr 15.0%, Mo 0.85%, P≤0.020%, S≤0.015%, B 1.10%, Ni 6.0%, Cu 2.5%, Nb 0.03%, Re 1.5%, and the balance is Fe and unavoidable impurities;

[0051] The nano-oxide addition part is composed of flaky zirconia nano-powder and rod-shaped yttrium oxide nano-powder in a mass ratio of 1:1.5 and obtained after ball milling treatment.

[0052] The preparation method of the nano-oxide addition material is as follows:

[0053] 1) 1.8 g of zirconium oxychloride was added to 8 mL of deionized water to dissolve it, and then 18 mL of phosphoric acid solution with a concentration of 3.2 mol / L was dropped in. During the dropping process, mechanical stirring at 700 r / min was accompanied to form a precursor sol. Then the precursor sol was transferred to a reaction kettle and hydrothermal reaction was carried out at 205 °C for 26 h. After the reaction ended, the obtained product was centrifuged and washed and dried at 75 °C to obtain nanosheet zirconia nanopowder;

[0054] 2) Yttrium nitrate was dissolved in deionized water to make a yttrium nitrate solution with a concentration of 0.3 mol / L. The pH value was adjusted to 12.5 with saturated sodium hydroxide solution, and then forward titration was adopted. The yttrium nitrate solution was titrated into the sodium hydroxide solution at an average speed of 2.3 mL / min to obtain a precipitate precursor. Then the precipitate precursor was transferred to a reaction kettle and hydrothermal reaction was carried out at 185 °C for 28 h. After the reaction, it was filtered, repeatedly washed with deionized water and absolute ethanol, vacuum dried at 85 °C for 5 h. The dried powder was placed in a calcination furnace and calcined at 630 °C for 7 h and naturally cooled to room temperature to obtain rod-shaped yttrium oxide nanopowder;

[0055] 3) The zirconia nanopowder and yttrium oxide nanopowder were mixed evenly according to a mass ratio of 1:1.5 to obtain an abrasive. Then the abrasive and water were mixed according to a mass ratio of 1:1 and poured into a ball mill. Using zirconia balls as the grinding medium, ball milling was carried out at a ball-to-material ratio of 3:1 for 1.5 h. After the treatment ended, the product was centrifuged, washed and dried to obtain the required nano-oxide addition part.

[0056] The base metal powder part was obtained by gas atomization method, and the base metal powder part and the nano-oxide addition part were mixed evenly to obtain the metal powder material.

[0057] The usage method of using this metal powder material for wheel repair includes the following steps:

[0058] S1. The defective position of the wheel to be repaired was manually polished to remove the surface oxide layer, stains and surface fatigue cracks, and wiped with alcohol, and then penetrant flaw detection was carried out to confirm that there were no cracks, holes and other residual defects unfavorable for laser cladding repair in the area to be repaired. Then, by measuring the length, width and depth of the area to be repaired, and according to the obtained data, the process program of laser cladding was compiled;

[0059] S2. Under the action of a 1.2T magnetic field, intermittent ultrasonic vibration is applied, and laser cladding is carried out using a fiber laser. The diameter of the focused laser spot for laser cladding is 5 mm, the scanning rate is set at 15 mm / s, the laser power range is 2000 W, and the laser energy is evenly distributed within the spot plane; during the cladding process, argon with a purity greater than 99.9% is used as the carrier gas for the metal powder and the shielding gas for the molten pool. The flow rate of the carrier gas for the metal powder is 8 L / min, the flow rate of the shielding gas for the molten pool is 16 L / min, and the feeding speed of the metal powder is set at 20 g / min;

[0060] This intermittent ultrasonic vibration has a power of 250 W. The ultrasonic vibration device that generates ultrasonic waves is non-contact with the wheel, and the ultrasonic vibration device will stop working for 25 s after continuously operating for 2 min and then act again, repeating this cycle;

[0061] S3. After the laser cladding is completed, penetrant flaw detection is carried out on the repaired area of the wheel to determine that no crack and hole defects are shown. A portable grinding machine is used to grind the laser cladding allowance in the repaired area of the wheel to restore the size and shape of the wheel, and the surface quality of the defect repaired area of the wheel meets the usage requirements. Finally, ultrasonic flaw detection is used to detect the defect repaired area to ensure that there are no internal defects affecting the use safety in the repaired wheel.

[0062] Example 3

[0063] A metal powder material for repairing high-speed train wheels, the metal powder material includes a basic metal powder part and a nano-oxide addition part. The nano-oxide addition part is 1.6% of the total mass of the basic metal powder part. Among them,

[0064] The composition and mass percentage of the basic metal powder part are: C≤0.56%, Si≤0.40%, Mn≤0.80%, Cr 20.0%, Mo 1.25%, P≤0.020%, S≤0.015%, B 1.80%, Ni 7.0%, Cu 3.0%, Nb 0.05%, Re 1.8%, and the balance is Fe and unavoidable impurities;

[0065] The nano-oxide addition part is composed of flaky zirconia nano-powder and rod-shaped yttrium oxide nano-powder in a mass ratio of 1:1.6 and obtained after ball milling treatment.

[0066] The preparation method of the nano-oxide addition material is as follows:

[0067] 1) Add 2.3 g of zirconium oxychloride to 10 mL of deionized water to dissolve it, and then drop 20 mL of phosphoric acid solution with a concentration of 3.4 mol / L. During the dropping process, mechanical stirring is carried out at 800 r / min to form a precursor sol. Then transfer the precursor sol to a reaction kettle and carry out a hydrothermal reaction at 210 °C for 30 h. After the reaction is completed, the obtained product is centrifuged and washed and dried at 80 °C to obtain nano-sheet zirconia nano-powder;

[0068] 2) Dissolve yttrium nitrate in deionized water to make a yttrium nitrate solution with a concentration of 0.5 mol / L. Adjust the pH value to 13 with saturated sodium hydroxide solution, and then use forward titration to titrate the yttrium nitrate solution into the sodium hydroxide solution at an average speed of 2.6 mL / min to obtain a precipitate precursor. Then transfer the precipitate precursor to a reaction kettle and carry out a hydrothermal reaction at 186 °C for 30 h. After the reaction, filter it, and repeatedly wash it with deionized water and absolute ethanol. Dry it in vacuum at 90 °C for 6 h. Place the dried powder in a calcination furnace and calcine it at 650 °C for 8 h, and naturally cool it to room temperature to obtain rod-shaped yttrium oxide nano-powder;

[0069] 3) Mix the zirconia nano-powder and yttrium oxide nano-powder evenly according to a mass ratio of 1:1.6 to obtain an abrasive. Then mix the abrasive and water according to a mass ratio of 1:1.1 and pour them into a ball mill. Use zirconia balls as the grinding medium and ball mill for 2 h according to a ball-to-material ratio of 3:1. After the treatment is completed, centrifuge and wash the product and then dry it to obtain the required nano-oxide addition part.

[0070] Obtain the base metal powder part by gas atomization method, and mix the base metal powder part and the nano-oxide addition part evenly to obtain the metal powder material.

[0071] The usage method of using this metal powder material for wheel repair includes the following steps:

[0072] S1. Manually grind the defective position of the wheel to be repaired to remove the surface oxide layer, stains and surface fatigue cracks, wipe it with alcohol, and then carry out penetrant flaw detection to confirm that there are no cracks, holes and other residual defects that are not conducive to laser cladding repair in the area to be repaired. Then measure the length, width and depth of the area to be repaired, and write the laser cladding process program according to the obtained data;

[0073] S2. Under the action of a 1.2T magnetic field, intermittent ultrasonic vibration is applied, and laser cladding is carried out using a fiber laser. The diameter of the focused laser spot for laser cladding is 10 mm, the scanning rate is set at 20 mm / s, the laser power range is 3000 W, and the laser energy is evenly distributed within the spot plane; during the cladding process, argon with a purity greater than 99.9% is used as the carrier gas for the metal powder and the molten pool protection gas. The flow rate of the metal powder carrier gas is 10 L / min, the flow rate of the molten pool protection gas is 20 L / min, and the metal powder feeding speed is set at 25 g / min;

[0074] This intermittent ultrasonic vibration has a power of 300 W. The ultrasonic vibration device that generates ultrasonic waves is non-contact with the wheel, and the ultrasonic vibration device stops working for 30 s after continuously operating for 2 min and then acts again, repeating this cycle;

[0075] S3. After the laser cladding is completed, penetrant flaw detection is performed on the repaired area of the wheel to determine that no crack and hole defects are shown. A portable grinding machine is used to grind the laser cladding allowance in the repaired area of the wheel to restore the size and shape of the wheel, and the surface quality of the defect repair area of the wheel reaches the usage requirements. Finally, ultrasonic flaw detection is used to detect the defect repair area to ensure that the repaired wheel has no internal defects that affect the use safety.

[0076] Comparative Example 1

[0077] It is the same as Example 1 except that the metal powder material does not contain the nano-oxide addition part.

[0078] Comparative Example 2

[0079] It is the same as Example 1 except that the nano-oxide addition part in the metal powder material does not contain zirconia nano-powder.

[0080] Comparative Example 3

[0081] It is the same as Example 1 except that the nano-oxide addition part in the metal powder material does not contain yttrium oxide nano-powder.

[0082] Comparative Example 4

[0083] It is the same as Example 1 except that the nano-oxide addition part in the metal powder material is not ground and mixed.

[0084] Comparative Example 5

[0085] It is the same as Example 1 except that the magnetic field action is omitted when using the metal powder material for laser cladding repair of the wheel.

[0086] Comparative Example 6

[0087] It is the same as Example 1 except that intermittent ultrasonic vibration is omitted when using metal powder materials for laser cladding repair of the wheel.

[0088] Test experiment:

[0089] Using the metal powder materials and preparation and usage methods provided in Examples 1-3 and Comparative Examples 1-6, defective wheels of the same batch were repaired, and then the quality of the cladding layer was observed. The results are shown in Table 1.

[0090] Table 1

[0091] Quality of the clad layer Example 1 The surface quality of the clad layer is good and there are no obvious defects Example 2 The surface quality of the clad layer is good and there are no obvious defects Example 3 The surface quality of the clad layer is good and there are no obvious defects Comparative Example 1 The quality of the clad layer is poor and there are clear hole defects Comparative Example 2 The quality of the clad layer is relatively poor and there are slight hole defects Comparative Example 3 The quality of the clad layer is relatively poor and there are slight hole defects Comparative Example 4 The quality of the clad layer is relatively poor and there are slight hole defects Comparative Example 5 The quality of the clad layer is relatively poor and there are slight hole defects Comparative Example 6 The quality of the clad layer is relatively poor and there are slight hole defects

[0092] It can be seen from Table 1 that the combination of the metal powder materials and the usage method in the present invention can effectively repair wheel defects in laser cladding, and the surface quality of the cladding layer is good, and metallurgical bonding can be formed, ensuring that the repaired position can be perfectly integrated with the wheel, meeting the normal safety performance requirements, avoiding or reducing the replacement of the wheel, and reducing the maintenance cost.

[0093] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art in the technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A metal powder material for repairing high-speed train wheels, characterized in that, The metal powder material includes a base metal powder part and a nano-oxide addition part. The nano-oxide addition part is 1.0 - 1.6% of the total mass of the base metal powder part. Among them, the composition and mass percentage of the base metal powder part are: C ≤ 0.56%, Si ≤ 0.40%, Mn ≤ 0.80%, Cr 10.0 - 20.0%, Mo 0.30 - 1.25%, P ≤ 0.020%, S ≤ 0.015%, B 0.20 - 1.80%, Ni 5.0 - 7.0%, Cu 2.0 - 3.0%, Nb 0.02 - 0.05%, Re 1.2 - 1.8%, and the balance is Fe and unavoidable impurities; the nano-oxide addition part is composed of zirconia nano-powder and yttria nano-powder, and the mass ratio of zirconia nano-powder to yttria nano-powder is 1:(1.0 - 1.6).

2. The metal powder material for repairing high-speed train wheels according to claim 1, characterized in that, The nano-oxide addition part is obtained by ball-milling and mixing zirconia nano-powder and yttria nano-powder.

3. The preparation method of the metal powder material for repairing high-speed train wheels according to claim 1 or 2, characterized in that, The preparation method includes the following steps for preparing the nano-oxide addition part: (1) Add zirconium oxychloride to deionized water to dissolve it, and then drop in phosphoric acid solution. During the dropping process, mechanical stirring is accompanied to form a precursor sol. Then transfer the obtained precursor sol to a reaction kettle for hydrothermal reaction for 24 - 30 h. After the reaction ends, wash the obtained product by centrifugation and dry it at 70 - 80 °C to obtain flaky zirconia nano-powder; (2) Dissolve yttrium nitrate in deionized water to obtain a yttrium nitrate solution. Adjust the pH value of the saturated sodium hydroxide solution to 12 - 13, and then use forward titration to titrate the yttrium nitrate solution into the above sodium hydroxide solution at an average speed of 2.0 - 2.6 mL / min to obtain a precipitate precursor; transfer the precipitate precursor to a reaction kettle for hydrothermal reaction for 24 - 30 h. After the reaction, filter it, wash it with deionized water and absolute ethanol, and vacuum-dry it at 80 - 90 °C for 4 - 6 h. Place the dried powder in a calcination furnace for calcination for 5 - 8 h and cool it naturally to room temperature to obtain rod-shaped yttria nano-powder; (3) Mix the zirconia nano-powder and yttria nano-powder evenly to obtain an abrasive, then mix the abrasive with water and pour it into a ball mill. Use zirconia balls as the grinding medium and ball-mill for 1 - 2 h according to a ball-to-material ratio of (2 - 3):

1. After the treatment ends, wash the product by centrifugation and dry it to obtain the nano-oxide addition part.

4. The preparation method according to claim 3, characterized in that In step (1), the ratio of zirconium oxychloride, deionized water, and phosphoric acid solution is (1.5 - 2.3) g:(5 - 10) mL:(15 - 20) mL, and the phosphoric acid solution is an aqueous solution with a concentration of 3.0 - 3.4 mol / L; the rotation speed of the mechanical stirring is 500 - 800 r / min; the temperature of the hydrothermal reaction is 200 - 210 °C.

5. The preparation method according to claim 3, characterized in that, In step (2), the concentration of the yttrium nitrate solution is 0.2 - 0.5 mol / L; the temperature of the hydrothermal reaction is 180 - 186 °C; the temperature of the calcination is 620 - 650 °C.

6. The preparation method according to claim 3, characterized in that, In step (3), the mass ratio of the abrasive to water is 1:(0.9 - 1.1).

7. The method of using the metal powder material for repairing high-speed train wheels according to claim 1 or 2, characterized in that The described usage method is used for laser cladding repair of high - speed train wheels and includes the following steps: S1. Grind the area to be repaired on the wheel to remove the surface oxide layer, stains and surface fatigue cracks, wipe it with alcohol, and then conduct penetrant flaw detection to confirm that there are no crack and hole defects in the area to be repaired; measure the length, width and depth of the area to be repaired, and write a process program for laser cladding according to the obtained data; S2. Under the action of a magnetic field, apply intermittent ultrasonic vibration, and use a fiber laser to perform laser cladding on the area to be repaired. Among them, use the metal powder material for repairing high - speed train wheels as the metal powder for laser cladding, and use argon with a purity greater than 99.9% as the metal powder carrier gas and molten pool protection gas during the cladding process; S3. After the laser cladding is completed, conduct penetrant flaw detection on the area treated by laser cladding again to determine that no crack and hole defects are shown; grind the laser cladding allowance to restore the size and wheel shape of the wheel, and make the surface quality of the repaired area of the wheel meet the usage requirements; finally, use ultrasonic flaw detection method to detect the repaired area of the wheel to ensure that there are no internal defects affecting the use safety in the repaired wheel.

8. The usage method according to claim 7, characterized in that, In step S2, the intensity of the magnetic field is 1.0 - 1.2T; the power of the intermittent ultrasonic vibration is 200 - 300W. The ultrasonic vibration device that generates ultrasonic waves is non - contact with the wheel, and the ultrasonic vibration device stops working for 20 - 30s after continuously working for 1 - 2min and then resumes working, and this cycle repeats.

9. The usage method according to claim 7, wherein, In step S2, the diameter of the focused laser spot for laser cladding is 2 - 10mm, and the scanning speed is set to 10 - 20mm / s; the laser power range used is 1500 - 3000W, and the laser energy is evenly distributed within the spot plane.

10. The usage method according to claim 7, characterized in that, In step S2, the flow rate of the metal powder carrier gas is 5 - 10L / min, the flow rate of the molten pool protection gas is 10 - 20L / min, and the metal powder feeding speed is set to 10 - 25g / min.