Preparation of laser cladding powder material and laser cladding repair method of shaft part

Abstract

The invention discloses a preparation method of a laser cladding powder material and a laser cladding repair method of a shaft part. The laser cladding powder material comprises 40 wt.%-85 wt.% of nickel-based alloy powder, 10 wt.%-30 wt.% of high-entropy alloy powder and 5 wt.%-30 wt.% of ceramic reinforced particles. The laser cladding powder material can be applied to ultrahigh-speed laser cladding repair of alloy steel shaft parts, the bonding strength between a cladding repair layer and a base body is high, the hardness of the cladding repair layer is high, and the internal stress of the repaired parts is small. By means of the process method for repairing abrasion or other defects in an ultra-high-speed laser cladding mode, the problems that the toughness of a repairing layer of the shaft part is reduced, and the residual stress is high are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cladding, and in particular to a laser cladding powder material and a preparation method thereof, and a laser cladding repair method for alloy steel shaft parts. Background Art

[0002] The main material used in wind turbine main shafts is alloy structural steel, which can meet the requirements of high-speed rotation and heavy loads. Alloy structural steel has excellent strength and toughness, and more importantly, it has good fatigue resistance in low temperature environments, which can ensure the stability and life of the main shaft during operation. 35CrMoA alloy steel has high static strength, impact toughness and fatigue limit, and also has excellent lasting strength at high temperatures. It is widely used in important structural parts working under high loads, such as wind turbine main shafts. During the operation of the wind turbine main shaft, it is subjected to periodic and random loads transmitted by the impeller, as well as torsional vibration loads of the transmission chain itself. Under the action of complex and variable loads, there are two main forms of failure and damage of the main shaft: one is that the local yield of the main shaft is damaged due to excessive limit loads; the other is that the main shaft is fatigued during its service life due to excessive alternating loads. Wind turbines are usually designed to operate safely and reliably for more than 20 years, or even longer. Therefore, the ultimate strength and fatigue strength of the main shaft must meet the requirements and have a certain safety reserve.

[0003] The main shaft may have defects such as metal inclusions, cracks, and rough surfaces during manufacturing. These defects will gradually expand during the operation of the main shaft and cause the main shaft to fail prematurely. The main shaft will also be affected by various environmental factors during long-term operation, such as temperature, humidity, vibration, etc. At the same time, the geometry of the main shaft will undergo slight deformation due to long-term operation, which will also cause the failure of the main shaft and eventually cause the wind turbine main shaft to be scrapped. After a period of service, the dimensional deformation and excessive wear of the components of the products entering the maintenance cycle are becoming more and more serious, and even destructive defects such as cracks may occur under extreme loads. Therefore, after a period of operation, the damaged parts of the wind turbine main shaft need to be repaired. At present, the damaged main shaft is mainly repaired by surfacing welding, but the residual stress of the main shaft after surfacing welding is high, and the surface hardness of the surfacing layer is high, and the hardness decreases with the increase of the distance from the surface layer. In addition, traditional cladding has a large welding heat input and a large welding heat affected zone during the welding process. The original mechanical properties of metal parts cannot be guaranteed after repair. In addition, the degree of automation in the welding process is low, and secondary defects are easily generated during cladding. When repairing overhauled products and precision-processed products, the product dimensional accuracy is difficult to guarantee, which greatly limits this method.

[0004] In addition, the scrapped spindle parts caused by the spindle not meeting the service conditions or other reasons can be reused through remanufacturing. However, remanufacturing uses recycled scrap spindle parts as raw materials. The instability of their quality leads to a great difference between the remanufacturing process and the new product manufacturing process, and there are many process uncertainty factors. Therefore, the remanufacturing quality of parts and the control of product quality consistency are more complex than new products. Laser cladding technology is mainly used for surface repair and modification of metal parts, and can also be used for spindle remanufacturing. However, the spindle remanufacturing process is uncertain due to the differences in the original quality of the spindle, service conditions, etc., especially the laser remanufacturing process, which has many process parameters, many influencing factors, and a complex process, resulting in the remanufacturing process being difficult to control and the remanufacturing quality consistency being poor.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a laser cladding powder material and a preparation method thereof and a laser cladding repair method for alloy steel shaft parts, so as to improve the above-mentioned technical problems.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a laser cladding powder material, comprising 40wt.% to 85wt.% of nickel-based alloy powder, 10wt.% to 30wt.% of high entropy alloy powder and 5wt.% to 30wt.% of ceramic reinforcement particles; wherein the chemical composition of the nickel-based alloy powder is: Cr: 3wt.% to 18wt.%, B: 1wt.% to 4wt.%, Si: 1wt.% to 6wt.%, Fe: 5wt.% to 20wt. %, C: 0.2wt.%~0.9wt.% and V: 0.1wt.%~0.3wt.%, and the balance is Ni; the chemical composition of the high entropy alloy powder is: Zr: 16wt.%~18.5wt.%, Al: 8wt.%~20wt.%, Ni: 9.5wt.%~13wt.%, Fe: 19wt.%~23wt.%, Cr: 18wt.%~22wt.% and Co: 20wt.%~24wt.%.

[0009] Optionally, the chemical composition of the nickel-based alloy powder is: Cr: 3wt.%~5wt.%, B: 1wt.%~3wt.%, Si: 2wt.%~4wt.%, Fe: 8wt.%~12wt.%, C: 0.2wt.%~0.6wt% and V: 0.1wt.%~0.3wt.%, and the balance is Ni.

[0010] Optionally, the content of nickel-based alloy powder in the laser cladding powder material is 55wt.% to 65wt.%, the content of high entropy alloy in the laser cladding powder material is 15wt.% to 25wt.%, and the content of ceramic reinforcement particles in the laser cladding powder material is 15wt.% to 25wt.%.

[0011] Optionally, the ceramic reinforcement particles are tungsten carbide reinforcement particles.

[0012] Optionally, the particle size of the laser cladding powder material is 15 μm to 50 μm.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned laser cladding powder material, which comprises: ball milling nickel-based alloy powder, high entropy alloy powder and ceramic reinforcement particles weighed in proportion through a ball mill.

[0014] Optionally, the ball mill is a planetary ball mill with a rotation speed of 10 r / min to 400 r / min and a ball milling time of 2 h to 24 h.

[0015] Optionally, the ball milling is performed under the protection of an inert gas.

[0016] Optionally, the particle size of the nickel-based alloy powder used for ball milling is 15μm to 75μm, the sphericity is ≥88%, the particle size of the high-entropy alloy powder used for ball milling is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforced particles used for ball milling is 3μm to 15μm.

[0017] Optionally, after ball milling, a laser cladding powder material with a size of 15 μm to 50 μm is obtained by sieving and grading.

[0018] In a third aspect, the present invention also provides a laser cladding repair method for alloy steel shaft parts, which comprises: repairing damaged parts of alloy steel shaft parts by ultra-high-speed laser cladding, and the laser cladding material used is the above-mentioned laser cladding powder material.

[0019] Optionally, the laser cladding operation conditions include: using inert gas as the protective gas, the powder feeding pressure is 0.05MPa~0.9MPa, and the powder feeding amount is 5g / min~45g / min; the power of the laser cladding equipment is 1kW~6kW; the thickness of the cladding layer is 0.2mm~5mm; the path trajectory of the laser cladding adopts a forward and reverse spiral trajectory motion mode, laser cladding and laser remelting are performed alternately, and the power of the laser remelting is 2~3 times that of the laser cladding.

[0020] Optionally, the laser spot diameter is 0.5 mm to 2 mm, the scanning rate is 20 m / min to 200 m / min, and the overlap rate is 45% to 60%.

[0021] Argon is used as the protective gas, the powder feeding pressure is 0.2-0.4 MPa, and the powder feeding amount is 18-25 g / min; the power of the laser cladding equipment is 1.8-2.5 kW, and the power of the laser remelting is 3.6-5 kW; the laser spot diameter is 0.8-1.2 mm, the scanning rate is 18-25 m / min, and the overlap rate is 45-55%.

[0022] Optionally, the laser cladding repair method for alloy steel shaft parts also includes: before laser cladding, removing rust stains, failed parts, and fatigue layers on the surface of the spindle, turning until the surface is free of wear or crack layers, and then laser preheating the spindle.

[0023] Optionally, after laser cladding, the spindle straightness and roundness are corrected by laser cleaning and annealing to ensure the machining allowances for turning and grinding, and then the spindle is repaired to a preset size by mechanical processing.

[0024] Optionally, the power of laser cleaning is 1kW to 2kW, the cleaning speed is 0.5m / min to 5m / min, the surface temperature of annealing correction is 900°C to 1000°C, the machining allowance of the spindle is 0.3mm to 0.5mm, and the surface roughness Ra≤0.3.

[0025] The present invention has the following beneficial effects: by introducing a specific proportion of ceramic reinforcement particles and high entropy alloy powder to improve the comprehensive performance of the cladding powder, the mixed alloy powder has excellent characteristics such as deoxidation, reduction, slag formation, degassing, wetting metal surface, good solid fluidity, moderate particle size, low oxygen content, etc. The addition of ceramic reinforcement particles can improve the hardness and wear resistance of the nickel-based alloy caused by the high nickel content, and the high entropy alloy stabilizes the chemically disordered solid solution phase by increasing the configuration entropy of the alloy, inhibits the formation of the ordered metal intermetallic compound competing with it, and the formed single-phase solid solution alloy has high strength and good plasticity. And the novel and unique composition design of the high entropy alloy can be well matched with the composition of the nickel-based alloy, and enhance the dispersion compatibility of the nickel-based alloy and the ceramic reinforcement particles. In addition to introducing alloy elements and interstitial elements to strengthen the matrix, it also uses the Al3Zr particles generated in situ as new nucleation sites in the grains, which can effectively inhibit the growth of the grains and improve the performance of the cladding layer. This laser cladding powder can be used for laser cladding repair of damaged positions on the surface of a damaged and failed spindle, and can achieve continuous multi-layer repair, breaking through the limitations of the number of repair layers of conventional powders and processes. The repaired structure is dense, free of cracks and unmelted powder, etc. There is no obvious height difference between the welds and the bonding is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 This is a microstructure diagram of the surface repaired by ultra-high-speed laser cladding according to Example 1 of the present invention;

[0028] Figure 2 This is a microstructure diagram of the surface repaired by ultra-high-speed laser cladding in Comparative Example 1 of the present invention;

[0029] Figure 3 This is a microstructure diagram of the surface repaired by ultra-high-speed laser cladding in Comparative Example 1 of the present invention;

[0030] Figure 4 This is a microstructure diagram of the surface repaired by ultra-high speed laser cladding in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0032] The following specifically describes a laser cladding powder material and a preparation method thereof and a laser cladding repair method for alloy steel shaft parts disclosed in the present invention.

[0033] After long-term high-speed operation, existing spindle parts will cause the spindle to vibrate, increase noise or rotate unstably, and will also cause problems such as wear, looseness or falling off. If the spindle is worn or deformed, it needs to be ground and repaired to restore the geometry and surface accuracy of the spindle. In order to achieve a better repair effect on the damaged parts of alloy steel shafts, it is necessary to make the laser cladding layer have an ideal stress distribution state. Furthermore, in order to obtain an ideal stress distribution state on the surface of the laser cladding layer, one method is to optimize the repair process, such as optimizing the laser cladding process parameters to obtain an ideal microstructure and performance; another method is to perform comprehensive organizational regulation by post-processing. Although residual stress can be released and the surface hardness of the cladding layer can be reduced by heat treatment, the heat treatment process cannot be carried out at the repair site, and the environmental protection investment is large, which is not suitable for on-site operations. The hammering method is widely used and more flexible, but the labor intensity is large, the controllability and surface quality are poor, and the effect is unstable. Shot peening can obtain relatively good mechanical properties, good controllability and effect, but the disadvantage is that the equipment is complex and large, the processing cost is high, and the flexibility is poor.

[0034] Therefore, after a lot of research and practice, the inventor proposed the use of ultra-high-speed laser cladding to repair or remanufacture alloy steel shaft parts. Unlike conventional laser cladding, ultra-high-speed laser cladding changes the laser optical path and powder feeding path. The high-energy laser beam is focused on the appropriate position above the metal substrate. The laser interacts with the metal substrate and the powder at the same time. The powder is melted before entering the substrate molten pool and enters the molten pool in liquid form. Compared with traditional surfacing methods, the ultra-high-speed laser cladding process significantly reduces the thermal impact of the substrate. At the same time, because laser cladding has extremely fast heating and cooling speeds, the thermal cycle process is short, and the grains of the cladding layer are not easy to grow, so that a uniform and dense internal microstructure can be formed, and defects such as pores and cracks are not easy to form. Based on the original quality of the spindle, service conditions, etc., it is necessary to find a laser cladding powder material suitable for the ultra-high-speed laser cladding process so that it can achieve better bonding strength and lower residual stress with the substrate, while also requiring higher hardness. This is undoubtedly a big challenge. Therefore, after further extensive research and practice, the following laser cladding powder materials and laser cladding repair methods were obtained.

[0035] Specifically, some embodiments of the present invention disclose a laser cladding powder material, which includes 40wt.% to 85wt.% of nickel-based alloy powder, 10wt.% to 30wt.% of high-entropy alloy powder and 5wt.% to 30wt.% of ceramic reinforcement particles. Among them, the chemical composition of the nickel-based alloy powder is: Cr: 3wt.%~18wt.%, B: 1wt.%~4wt.%, Si: 1wt.%~6wt.%, Fe: 5wt.%~20wt.%, C: 0.2wt.%~0.9wt%, V: 0.1wt.%~0.3wt.%, and the balance is Ni; the chemical composition of the high-entropy alloy powder is: Zr: 16wt.%~18.5wt.%, Al: 8wt.%~20wt.%, Ni: 9.5wt.%~13wt.%, Fe: 19wt.%~23wt.%, Cr: 18wt.%~22wt.%, Co: 20wt.%~24wt.%.

[0036] Generally speaking, adding nickel to the laser cladding layer can improve the toughness of the cladding layer, which is a very effective method to inhibit the generation of cracks. The above-mentioned laser cladding powder is mainly nickel-based alloy powder, which has good toughness and is suitable for laser cladding. However, its high nickel content will also lead to a decrease in the hardness of the cladding layer, reduce the service performance of the cladding layer, and its bonding performance with the surface of alloy steel shafts does not meet the requirements. Therefore, on this basis, a specific proportion of ceramic reinforcement particles and high entropy alloys are further added to improve the comprehensive performance of the cladding powder material, so that the mixed alloy powder has excellent properties such as deoxidation, reduction, slag formation, degassing, wetting metal surface, good solid fluidity, moderate particle size, and low oxygen content. Furthermore, in order to achieve better comprehensive performance, in some embodiments, the chemical composition of the nickel-based alloy powder and the ratio with the high entropy alloy powder and ceramic reinforcing particles are optimized. Exemplarily, the chemical composition of the nickel-based alloy powder is: Cr: 3wt.%~5wt.%, B: 1wt.%~3wt.%, Si: 2wt.%~4wt.%, Fe: 8wt.%~12wt.%, C: 0.2wt.%~0.6wt%, V: 0.1wt.%~0.3wt.%, and the balance is Ni. For reference, the content of nickel-based alloy powder in the laser cladding powder material is 55wt.% to 65wt.%, for example, 55wt.%, 56wt.%, 57wt.%, 58wt.%, 59wt.%, 60wt.%, 61wt.%, 62wt.%, 63wt.%, 64wt.% or 65wt.%, or between any two percentages; the content of high entropy alloy in the laser cladding powder material is 15wt.% to 25wt.%, for example, 15wt.%, 16wt.%, 17wt.%, 18wt.%. %, 19wt.%, 20wt.%, 21wt.%, 22wt.%, 23wt.%, 24wt.% or 25wt.%, or between any two percentages; the content of ceramic reinforcing particles in the laser cladding powder material is 15wt.% to 25wt.%, for example, 15wt.%, 16wt.%, 17wt.%, 18wt.%, 19wt.%, 20wt.%, 21wt.%, 22wt.%, 23wt.%, 24wt.% or 25wt.%, or between any two percentages.

[0037] In some embodiments, the ceramic reinforcement particles can be selected as tungsten carbide reinforcement particles. Tungsten carbide particles have high hardness, which can effectively improve the hardness of the cladding layer, and tungsten carbide particles have good interface bonding with nickel, and large amounts of tungsten carbide particles are not likely to cause cracking of the cladding layer. In addition, tungsten carbide particles have good thermal stability and low expansion coefficient, which is conducive to reducing thermal stress caused by temperature changes and enhancing corrosion resistance.

[0038] For reference, the particle size of the laser cladding powder material can be selected to be 15μm to 50μm. In the ultra-high-speed laser cladding process, on the one hand, the laser cladding powder in this particle size range is more likely to form a uniform molten pool on the substrate, which helps to improve the flatness and density of the cladding layer and avoid holes, cracks, etc.; on the other hand, the powder in this particle size range is more easily heated and melted by the laser beam, thereby improving the cladding efficiency and effect.

[0039] Furthermore, some embodiments of the present invention also provide a method for preparing the above-mentioned laser cladding powder material, which comprises: ball milling nickel-based alloy powder, high entropy alloy powder and ceramic reinforcement particles weighed in proportion through a ball mill.

[0040] Ball milling can make the three components evenly dispersed, and the ceramic reinforcement particles can be physically combined with the other two nickel-based alloy powders.

[0041] In some embodiments, the particle size of the nickel-based alloy powder used for ball milling is 15 μm to 75 μm, the sphericity is ≥ 88%, the particle size of the high-entropy alloy powder used for ball milling is 16 to 50 μm, the sphericity is ≥ 92%, the oxygen content is ≤ 150 ppm, and the particle size of the ceramic reinforcement particles used for ball milling is 3 μm to 15 μm. After ball milling, the ceramic reinforcement particles with smaller particle size can be combined with the nickel-based powder and high-entropy alloy powder with larger particle size under the action of mechanical force.

[0042] In some embodiments, the ball mill is a planetary ball mill, and the rotation speed can be selected to be 10r / min~400r / min, for example, 10r / min, 20r / min, 50r / min, 60r / min, 70r / min, 80r / min, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min or 400r / min, etc.; the ball milling time can be selected to be 2h~24h, for example, 2h, 5h, 8h, 10h, 12h, 15h, 18h, 20h or 24h, etc.

[0043] Furthermore, in some embodiments, the ball milling is performed under the protection of an inert gas, wherein the inert gas may be argon.

[0044] In some embodiments, high entropy alloy powder and nickel-based alloy powder are weighed in proportion and evenly mixed with tungsten carbide reinforced particles, and a planetary ball mill is used to rotate at a speed of 10 to 400 r / min for 2 to 24 hours. Argon gas is introduced during the ball milling process for protection. After the ball milling is completed, the laser cladding powder material with a particle size of 15 μm to 50 μm is obtained by sieving and grading.

[0045] Some embodiments of the present invention also provide a laser cladding repair method for alloy steel shaft parts, which comprises: repairing damaged parts of alloy steel shaft parts by ultra-high-speed laser cladding, and the laser cladding material used is the above-mentioned laser cladding powder material.

[0046] Ultra-high-speed laser cladding has a high cladding rate. During the cladding process, more than 85% of the laser energy directly acts on the repair powder, with ultra-low heat input and ultra-high powder capture efficiency. The base material is less damaged by heat, and the width of the heat-affected zone and the dilution rate of the cladding layer are low, which is conducive to improving the wear resistance and corrosion resistance of the cladding layer. The efficiency of ultra-high-speed laser cladding is 40 to 100 times higher than that of traditional laser cladding, so the cladding layer can be quickly prepared over a large area. Laser surface remelting uses a high-energy-density laser beam to irradiate the surface of the material, causing it to melt rapidly in a short time, and then rapidly cools and solidifies through the heat conduction and thermal convection of the substrate, thereby forming a layer of fine grain structure on the surface of the material. The repair layer prepared by ultra-high-speed laser cladding has the characteristics of high cooling rate, uniform element distribution, and dendrite refinement, which can further improve the corrosion resistance of the repair layer.

[0047] Therefore, ultra-high-speed laser cladding technology is easy to control automatically, and can achieve precise process parameter adjustment and stable cladding quality. The repaired spindle surface has high surface hardness, fatigue resistance, wear resistance and corrosion resistance, which can effectively improve the service life of the spindle and achieve the purpose of repair. The process is highly efficient, simple to operate, has a wide range of applications, and is convenient for industrial production and application. By adopting this repair method, it can be applied to the remanufacturing / repair of wind turbine main shafts, effectively regulate the surface structure of the laser remanufactured spindle, improve its service life, and obtain a high damage tolerance surface, which is of great significance for improving the operating safety of wind turbines, improving economic benefits, and saving resources and energy.

[0048] In some implementations, the laser cladding repair method for alloy steel shaft parts specifically includes:

[0049] S1. Inspection and preprocessing.

[0050] Specifically, in some embodiments, the spindle is cleaned and inspected to remove rust stains, failure sites, and fatigue layers on the surface, and then subjected to flaw detection and turning until there is no wear or crack layer on the surface; before laser cladding repair, the spindle is laser preheated. In some embodiments, the spindle is preheated to a surface temperature of 200 to 300°C using laser rapid scanning, and the laser power is 4 to 6kW.

[0051] In some embodiments, before laser cladding, the laser cladding powder material for repair is baked and dried at a temperature of 150 to 280° C. for 2 to 3 hours.

[0052] S2. Laser cladding and laser remelting.

[0053] Specifically, in some embodiments, an inert gas is used as a protective gas, and the powder feeding gas pressure is 0.05MPa to 0.9MPa. For example, it can be selected as 0.05MPa, 0.1MPa, 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa, 0.55MPa, 0.6MPa, 0.65MPa, 0.7MPa, 0.75MPa, 0.8MPa, 0.85MPa or 0.9MPa, or between any two of the above pressures; the powder feeding amount is 5g / min to 45g / min. For example, it can be selected as 5g / min, 10g / min, 15g / min, 20g / min, 25g / min, 30g / min, 35g / min, 40g / min, etc. g / min or 45g / min, etc., or between any two of the above powder feeding rates; the power of the laser cladding equipment is 1kW to 6kW, and for example, it can be selected as 1kW, 1.5kW, 2kW, 2.5kW, 3kW, 3.5kW, 4kW, 4.5kW, 5kW, 5.5kW or 6kW, etc., or between any two of the above powers; the thickness of the cladding layer is 0.2mm to 5mm, and for example, the thickness of the cladding layer can be selected as 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc., or between any two of the above thicknesses; the path trajectory of the laser cladding adopts a forward and reverse spiral trajectory motion mode, and the laser cladding and laser remelting are performed alternately, and the power of the laser remelting is 2 to 3 times that of the laser cladding, preferably 2 times. Among them, the inert gas used as the protective gas can be selected as argon with a purity greater than 99.99%.

[0054] In some embodiments, the laser spot diameter is 0.5 mm to 2 mm, and can be selected as 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2 mm, or between any two of the above diameters. The scanning rate is 20 m / min to 200 m / min, for example, it can be selected as 20 m / min, 25 m / min, 30 m / min, 35 m / min, 40 m / min, 50 m / min, 80 m / min, 100 m / min or 200 m / min, or between any two of the above scanning rates. The overlap rate is 45 to 60%, and can be selected as 50% for example.

[0055] In some embodiments, argon is used as the protective gas, the powder feeding pressure is 0.2-0.4 MPa, and the powder feeding amount is 18-25 g / min; the power of the laser cladding equipment is 1.8-2.5 kW, and the power of the laser remelting is 3.6-5 kW; the laser spot diameter is 0.8-1.2 mm, the scanning rate is 18-25 m / min, and the overlap rate is 45-55%.

[0056] In some implementations, the power of the laser cladding equipment is 2-4 kW or 2-3 kW, and the power of the laser remelting is 3.5-4.5 kW.

[0057] Exemplarily, argon is used as the protective gas, the powder feeding pressure is 0.3 MPa, and the powder feeding amount is 20 g / min; the power of the laser cladding equipment is 2 kW, and the power of the laser remelting is 4 kW; preferably, the laser spot diameter is 1 mm, the scanning rate is 20 m / min, and the overlap rate is 50%.

[0058] First, by strictly controlling the laser power and scanning rate, the cladding powder material can be completely melted and have appropriate energy input and heat accumulation, so that the cladding layer has better bonding strength and density, and is not prone to defects such as element burnout, pores and cracks, and avoids problems such as poor bonding between the cladding layer and the substrate, and the generation of coarse tissue and thermal stress. Secondly, by controlling the powder feeding rate, the flatness and uniformity of the cladding layer can meet the performance requirements. In addition, the reasonable setting of the spot diameter and overlap rate also enables the cladding layer to have better flatness and continuity, improving the quality of the cladding layer.

[0059] S3. Correction and post-processing.

[0060] Specifically, after laser cladding, the spindle straightness and roundness are corrected by laser cleaning and annealing to ensure the machining allowance for turning and grinding, and then the spindle is repaired to the preset size by mechanical processing.

[0061] Annealing can make the atoms inside the material obtain enough energy to rearrange, thereby effectively reducing or even eliminating residual stress, reducing the risk of cracking of the cladding layer, and promoting the growth and homogenization of grains, making the organization more stable and uniform, thereby improving the mechanical properties of the cladding layer, such as improving toughness and ductility. In addition, after annealing, the microstructure of the material is optimized, and defects such as grain boundaries and dislocations are reduced, thereby reducing the intrusion channels of corrosive media and improving the corrosion resistance of the cladding layer. It also reduces this hardness difference to a certain extent, making the hardness distribution more gentle, which helps to improve the overall performance and service life of the workpiece.

[0062] In some embodiments, the power of laser cleaning is 1kW to 2kW, the cleaning speed is 0.5m / min to 5m / min, the surface temperature of annealing correction is 900℃ to 1000℃, and then air-cooled, the machining allowance of the spindle is 0.3mm to 0.5mm, and the surface roughness Ra≤0.3.

[0063] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0064] The spindles in the following examples and comparative examples are sourced from 42CrMoA alloy bars produced by Guangdong Shaoguan Iron & Steel Co., Ltd. The tests of bonding strength, surface average hardness and residual internal stress were carried out in accordance with GB / T 39685-2020, GB / T231.1-2002 and ASTM E915-2010 standards.

[0065] Example 1

[0066] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0067] 30% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 10% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) are weighed in proportion and uniformly mixed, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0068] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0069] S1. Inspection and preprocessing

[0070] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0071] S2. Laser cladding and laser remelting

[0072] Argon with a purity greater than 99.99% was used as the protective gas, and the powder feeding pressure was 0.3MPa; the repair powder was baked and dried at a temperature of 160°C for 2 hours; the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment were used for surface repair, and the laser power was 2kW; the thickness of the cladding layer was 2mm. The path trajectory of the laser cladding adopted a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting were performed alternately, and the power of the laser remelting was 4kW. The laser spot diameter was 1mm, the scanning rate was 20m / min, and the overlap rate was 50%.

[0073] S3, correction and post-processing

[0074] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0075] The laser cladding repair layer prepared in this embodiment has a dense structure and no cracks ( Figure 1 ), the bonding strength between the repair layer and the substrate is 586MPa, the average surface hardness is HRC62, and the residual internal stress is -249MPa.

[0076] Example 2

[0077] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0078] Weigh 20% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 20% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) in proportion and mix them uniformly, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0079] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0080] S1. Inspection and preprocessing

[0081] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0082] S2. Laser cladding and laser remelting

[0083] Argon with a purity greater than 99.99% was used as the protective gas, and the powder feeding pressure was 0.3MPa; the repair powder was baked and dried at a temperature of 160°C for 2 hours; the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment were used for surface repair, and the laser power was 2kW; the thickness of the cladding layer was 2mm. The path trajectory of the laser cladding adopted a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting were performed alternately, and the power of the laser remelting was 4kW. The laser spot diameter was 1mm, the scanning rate was 20m / min, and the overlap rate was 50%.

[0084] S3, correction and post-processing

[0085] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0086] The laser cladding repair layer prepared in this embodiment has a dense structure and no cracks. The bonding strength between the repair layer and the substrate is 581 MPa, the average surface hardness is HRC63, and the residual internal stress is -238 MPa.

[0087] Example 3

[0088] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0089] 10% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 30% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) are weighed in proportion and uniformly mixed, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0090] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0091] S1. Inspection and preprocessing

[0092] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0093] S2. Laser cladding and laser remelting

[0094] Argon with a purity greater than 99.99% was used as the protective gas, and the powder feeding pressure was 0.3MPa; the repair powder was baked and dried at a temperature of 160°C for 2 hours; the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment were used for surface repair, and the laser power was 2kW; the thickness of the cladding layer was 2mm. The path trajectory of the laser cladding adopted a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting were performed alternately, and the power of the laser remelting was 4kW. The laser spot diameter was 1mm, the scanning rate was 20m / min, and the overlap rate was 50%.

[0095] S3, correction and post-processing

[0096] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0097] The laser cladding repair layer prepared in this embodiment has a dense structure and no cracks. The bonding strength between the repair layer and the substrate is 574 MPa, the average surface hardness is HRC65, and the residual internal stress is -231 MPa.

[0098] Example 4

[0099] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0100] 10% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 30% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) are weighed in proportion and uniformly mixed, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0101] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0102] S1. Inspection and preprocessing

[0103] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0104] S2. Laser cladding and laser remelting

[0105] Argon with a purity greater than 99.99% is used as the protective gas, and the powder feeding pressure is 0.3MPa; the repair powder is baked and dried at a temperature of 160°C for 2 hours; the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment are used for surface repair, and the laser power is 3kW; the thickness of the cladding layer is 2mm. The path trajectory of the laser cladding adopts a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting are performed alternately, and the power of the laser remelting is 4kW. The laser spot diameter is 1mm, the scanning rate is 30m / min, and the overlap rate is 50%.

[0106] S3, correction and post-processing

[0107] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0108] The laser cladding repair layer prepared in this embodiment has a dense structure and no cracks. The bonding strength between the repair layer and the substrate is 559 MPa, the average surface hardness is HRC66, and the residual internal stress is -226 MPa.

[0109] Example 5

[0110] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0111] 10% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 30% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) are weighed in proportion and uniformly mixed, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0112] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0113] S1. Inspection and preprocessing

[0114] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0115] S2. Laser cladding and laser remelting

[0116] Argon with a purity greater than 99.99% was used as the protective gas, and the powder feeding pressure was 0.3MPa; the repair powder was baked and dried at a temperature of 160°C for 2 hours; the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment were used for surface repair, and the laser power was 4kW; the thickness of the cladding layer was 2mm. The path trajectory of the laser cladding adopted a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting were performed alternately, and the power of the laser remelting was 4kW. The laser spot diameter was 1mm, the scanning rate was 30m / min, and the overlap rate was 50%.

[0117] S3, correction and post-processing

[0118] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0119] The laser cladding repair layer prepared in this embodiment has a dense structure and no cracks. The bonding strength between the repair layer and the substrate is 552 MPa, the average surface hardness is HRC65, and the residual internal stress is -237 MPa.

[0120] Comparative Example 1

[0121] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0122] 10% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 30% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) are weighed in proportion and uniformly mixed, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0123] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0124] S1. Inspection and preprocessing

[0125] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0126] S2. Laser cladding and laser remelting

[0127] Argon with a purity greater than 99.99% is used as the protective gas, and the powder feeding pressure is 0.3MPa; the repair powder is baked and dried at a temperature of 160°C for 2 hours; the surface repair is performed using the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment, with a laser power of 5kW; the thickness of the cladding layer is 2mm. The path trajectory of the laser cladding adopts a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting are performed alternately, with a laser remelting power of 5kW. The laser spot diameter is 1mm, the scanning rate is 30m / min, and the overlap rate is 50%.

[0128] S3, correction and post-processing

[0129] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0130] The laser cladding repair layer prepared in this embodiment is not dense and has microcracks ( Figure 2 , Figure 3 ).

[0131] Comparative Example 2

[0132] This embodiment provides a laser cladding powder material, which is prepared by the following steps:

[0133] 10% by mass of high entropy alloy powder (Zr: 17wt.%, Al: 16.5wt.%, Ni: 9.5wt.%, Fe: 19wt.%, Cr: 18wt.%, Co: 20wt.%), 30% by mass of tungsten carbide reinforcement particles and 60% by mass of nickel-based alloy powder (Cr: 4wt.%, B: 2wt.%, Si: 3wt.%, Fe: 10wt.%, C: 0.4wt.%, V: 0.2wt.%, and the balance is Ni) are weighed in proportion and uniformly mixed, wherein the particle size of the nickel-based alloy powder is 15μm to 75μm, and the sphericity is ≥88%, the particle size of the high entropy alloy powder is 16 to 50μm, the sphericity is ≥92%, the oxygen content is ≤150ppm, and the particle size of the ceramic reinforcement particles is 3μm to 15μm. A planetary ball mill was used with a rotation speed of 200 r / min for 12 h. Argon gas was introduced for protection during the ball milling process. After the ball milling was completed, the laser cladding powder material with a particle size of 15 to 50 μm was obtained by sieving and grading.

[0134] This embodiment also provides a laser cladding repair method for alloy steel shaft parts, the method comprising the following steps:

[0135] S1. Inspection and preprocessing

[0136] The spindle surface is sandblasted to remove oil and rust attached to the surface, and then the remaining rust is cleaned with sandpaper; the wear and failure parts and fatigue layer on the spindle surface are removed by turning, and a flaw detection inspection is performed every 0.5mm of turning until there is no wear or cracks on the surface; then the overall circular runout, ovality, wear degree and hardness test of the spindle are checked; before laser cladding repair, the spindle is laser preheated with a laser preheating power of 4kW and a scanning time of 10min.

[0137] S2. Laser cladding and laser remelting

[0138] Argon with a purity greater than 99.99% is used as the protective gas, and the powder feeding pressure is 0.3MPa; the repair powder is baked and dried at a temperature of 160°C for 2 hours; the above-mentioned laser cladding powder material and ultra-high-speed laser cladding equipment are used for surface repair, and the laser power is 6kW; the thickness of the cladding layer is 2mm. The path trajectory of the laser cladding adopts a spiral trajectory (forward and reverse) motion mode, and laser cladding and laser remelting are performed alternately, and the power of the laser remelting is 6kW. The laser spot diameter is 1mm, the scanning rate is 40m / min, and the overlap rate is 50%.

[0139] S3, correction and post-processing

[0140] The spindle straightness and roundness after laser cladding repair are laser cleaned and corrected. The spindle laser cleaning power is 1.5kW, the cleaning speed is 1m / min, the spindle surface temperature is 950℃ for annealing correction, and then air cooling is performed; the turning thickness is 0.1mm, and then grinding is performed. The surface roughness of the spindle after grinding is Ra≤0.3. The appearance, dimensional accuracy and performance of the spindle are tested, and there should be no cracks, pores and bumps on the appearance surface. The dimensional accuracy must meet the upper deviation of 0 and the lower deviation of -0.03mm.

[0141] The laser cladding repair layer prepared in this embodiment is not dense and has microcracks ( Figure 4 ). In summary, by using the laser cladding powder material of the specific composition of the embodiment of the present invention to perform ultra-high-speed laser cladding operation under specific laser cladding parameters, the bonding strength between the formed cladding repair layer and the substrate can be greater than 520MPa, the surface hardness HRC ≥ 62, and the performance of the cladding repair layer is better than that of the spindle substrate material, and it can serve for a long time under harsh working conditions. Compared with traditional laser cladding, ultra-high-speed laser cladding technology has a small dilution degree, dense structure, and good bonding between the coating and the substrate, ensuring a high-quality cladding layer. The cladding layer is flat and can be directly ground and polished without turning, which greatly saves material and processing costs.

[0142] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser cladding powder material, It is characterized in that The invention comprises 40wt.% to 85wt.% of nickel-based alloy powder, 10wt.% to 30wt.% of high entropy alloy powder and 5wt.% to 30wt.% of ceramic reinforcement particles; The chemical composition of the nickel-based alloy powder is as follows: Cr: 3wt.% to 18wt.%, B: 1wt.% to 4wt.%, Si: 1wt.% to 6wt.%, Fe: 5wt.% to 20wt.%, C: 0.2wt.% to 0.9wt% and V: 0.1wt.% to 0.3wt.%, and the balance is Ni; The chemical composition of the high entropy alloy powder is: Zr: 16wt.%~18.5wt.%, Al: 8wt.%~20wt.%, Ni: 9.5wt.%~13wt.%, Fe: 19wt.%~23wt.%, Cr: 18wt.%~22wt.% and Co: 20wt.%~24wt.%.

2. The laser cladding powder material according to claim 1, It is characterized in that The chemical composition of the nickel-based alloy powder is: Cr: 3wt.% to 5wt.%, B: 1wt.% to 3wt.%, Si: 2wt.% to 4wt.%, Fe: 8wt.% to 12wt.%, C: 0.2wt.% to 0.6wt% and V: 0.1wt.% to 0.3wt.%, and the balance is Ni; And / or, the content of the nickel-based alloy powder in the laser cladding powder material is 55wt.% to 65wt.%, the content of the high entropy alloy in the laser cladding powder material is 15wt.% to 25wt.%, and the content of the ceramic reinforcement particles in the laser cladding powder material is 15wt.% to 25wt.%.

3. The laser cladding powder material according to claim 1 or 2, It is characterized in that The ceramic reinforcement particles are tungsten carbide reinforcement particles; And / or, the particle size of the laser cladding powder material is 15 μm to 50 μm.

4. A method for preparing a laser cladding powder material according to any one of claims 1 to 3, It is characterized in that It includes: The nickel-based alloy powder, the high entropy alloy powder and the ceramic reinforcement particles weighed in proportion are ball-milled by a ball mill.

5. The method for preparing the laser cladding powder material according to claim 4, It is characterized in that The ball mill is a planetary ball mill with a rotation speed of 10r / min to 400r / min and a ball milling time of 2h to 24h; Preferably, the ball milling is performed under the protection of an inert gas.

6. The method for preparing the laser cladding powder material according to claim 4 or 5, It is characterized in that The particle size of the nickel-based alloy powder used for ball milling is 15 μm to 75 μm, the sphericity is ≥88%, the particle size of the high-entropy alloy powder used for ball milling is 16 to 50 μm, the sphericity is ≥92%, the oxygen content is ≤150 ppm, and the particle size of the ceramic reinforcement particles used for ball milling is 3 μm to 15 μm; Preferably, after ball milling, the laser cladding powder material with a size of 15 μm to 50 μm is obtained by sieving and grading.

7. A laser cladding repair method for alloy steel shaft parts. It is characterized in that It includes: Ultra-high-speed laser cladding is used to repair the damaged parts of the alloy steel shaft parts, and the laser cladding material used is the laser cladding powder material according to any one of claims 1 to 3.

8. The laser cladding repair method according to claim 7, It is characterized in that The operating conditions of laser cladding include: using inert gas as protective gas, powder feeding pressure of 0.05-0.9 MPa, powder feeding amount of 5g / min-45g / min; the power of laser cladding equipment is 1kW-6kW; the thickness of cladding layer is 0.2mm-5mm; the path trajectory of laser cladding adopts the forward and reverse spiral trajectory motion mode, laser cladding and laser remelting are carried out alternately, and the power of laser remelting is 2-3 times that of laser cladding; Preferably, the laser spot diameter is 0.5 mm to 2 mm, the scanning rate is 20 m / min to 200 m / min, and the overlap rate is 45% to 60%.

9. The laser cladding repair method according to claim 8, It is characterized in that Argon is used as the protective gas, the powder feeding pressure is 0.2-0.4 MPa, and the powder feeding amount is 18-25 g / min; the power of the laser cladding equipment is 1.8-2.5 kW, and the power of the laser remelting is 3.6-5 kW; Preferably, the laser spot diameter is 0.8-1.2 mm, the scanning rate is 18-25 m / min, and the overlap rate is 45-55%.

10. The laser cladding repair method according to any one of claims 7 to 9, It is characterized in that It also includes: before laser cladding, removing rust stains, failure parts, and fatigue layers on the surface of the spindle, turning until there is no wear or crack layer on the surface, and then laser preheating the spindle; Preferably, after laser cladding, the spindle straightness and roundness are corrected by laser cleaning and annealing to ensure the machining allowances of turning and grinding, and then the spindle is repaired to a preset size by mechanical processing; Further preferably, the power of laser cleaning is 1kW to 2kW, the cleaning speed is 0.5m / min to 5m / min, the surface temperature of annealing correction is 900°C to 1000°C, the machining allowance of the spindle is 0.3mm to 0.5mm, and the surface roughness Ra≤0.3.

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