Preparation method of nickel-based WC alloy coating on surface of glass mold punch

Abstract

The invention provides a preparation method of a nickel-based WC alloy coating on the surface of a glass mold punch. The preparation method sequentially comprises the steps of matrix pretreatment, hypersonic flame spraying, ultrahigh-speed laser remelting and aftertreatment. The nickel-based WC alloy coating is prepared on the surface of the glass mold punch by adopting a supersonic spraying and ultra-high-speed laser remelting composite process, on one hand, a mechanical interlocking framework is formed by adopting nano-scale WC powder and micron-scale WC powder composite double-peak gradient powder, rare earth oxide is doped, nano-particle aggregation is inhibited through a vacuum ball-milling process, and the mechanical interlocking framework is formed by adopting a double-peak gradient powder composite double-peak gradient powder; the compactness of a cladding layer is improved; and on the other hand, the parameters of the composite technology are controlled, it is guaranteed that nanoscale WC is completely dissolved in a molten pool, a W-C-Fe diffusion layer is formed on an interface, a WC / W2C hard phase is separated out after micron-sized WC is partially dissolved, the bonding strength is improved, and the compactness and hardness of the coating are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of surface engineering and glass mold manufacturing, and particularly to a method for preparing a nickel-based WC alloy coating on the surface of a glass mold punch. Background Art

[0002] The glass mold punch plays a crucial role in the glass manufacturing process. Due to its harsh working environment, during the glass forming process, it needs to withstand the erosion of high-temperature glass melt (1000 - 1200 °C) and periodic high-pressure friction (10 - 50 MPa) for a long time. Therefore, extremely high requirements are imposed on the performance of the coating material, and high bonding strength and high density need to be ensured.

[0003] Nickel-based WC alloy coatings are widely used in the surface strengthening of glass mold punches due to their good hardness, wear resistance, and high-temperature resistance. Currently, the coating preparation processes mainly include high-velocity oxy-fuel spraying (HVOF), laser cladding, induction heating remelting, and manual flame remelting. However, these processes have many problems:

[0004] 1. High-velocity oxy-fuel spraying (HVOF): Although WC particles can be refined to 10 - 30 μm, the coating and the substrate are mechanically bonded (bonding strength < 80 MPa). After 100 high-low temperature cycles ( ), the spalling area of the coating > 30%.

[0005] 2. Laser cladding: WC particles agglomerate due to uneven heat input (particle size > 50 μm), the hardness fluctuation of the coating > 200 HV, and orange peel-like cracks (depth > 40 μm) are formed on the surface after high-temperature oxidation, reducing the service life by more than 50%.

[0006] 3. Induction heating remelting / manual flame remelting: The temperature fluctuates by ±150 °C, the heating time deviation is ±30%, the porosity > 8%, the defective rate > 15%, and it depends on manual operation and cannot achieve automated continuous production.

[0007] It can be seen that the existing coating preparation processes cannot balance the coating bonding strength, density, surface quality, and process stability, resulting in a short service life of the glass mold punch and high production costs. Summary of the Invention

[0008] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a method for preparing a nickel-based WC alloy coating on the surface of a glass mold punch, which is used to solve the problem that the existing coating preparation processes in the prior art cannot meet the high-performance requirements of glass mold punches.

[0009] To achieve the above object and other related objects, the present invention provides a method for preparing a nickel-based WC alloy coating on the surface of a glass mold punch, including the following steps:

[0010] (1) Pretreat the substrate;

[0011] (2) Prepare a nickel-based WC alloy coating on the surface of the substrate by supersonic spraying. The powder used is nickel-based WC alloy powder, and the nickel-based WC alloy powder includes the following components by mass percentage: B: 1-1.2%, Co: 3.8-4.2%, Cr: 6.8-7.5%, Fe: 1.8-2.2%, Si: 2.0-2.5%, WC: 30-35%, rare earth oxide: 0.5-1.0%, and the balance is Ni;

[0012] (3) Perform ultra-high-speed laser remelting treatment on the nickel-based WC alloy coating in step (2);

[0013] (4) Air-cool the coating after the ultra-high-speed laser remelting treatment.

[0014] Further, in step (1), the pretreatment includes substrate surface cleaning and substrate preheating.

[0015] Further still, the substrate surface cleaning includes: ultrasonically cleaning the substrate surface with an organic solvent such as acetone or alcohol to remove the oil and impurities on its surface, and then grinding the cleaned substrate surface to a precision of Ra 0.8-1.6 μm to increase the surface roughness of the substrate and enhance the bonding force between the coating and the substrate;

[0016] The substrate preheating includes: placing the cleaned and ground substrate in a constant-temperature heating device and preheating it at 100-200 °C for 5-15 minutes to reduce the thermal stress during the supersonic spraying process.

[0017] Further, in the nickel-based WC alloy powder of step (2), WC is a bimodal gradient composite powder of nano-scale WC and micro-scale WC. Among them, the size range of nano-scale WC is 300-500 nm, and the content is 30-50 wt%; the size range of micro-scale WC is 15-35 μm, and the content is 50-70 wt%.

[0018] Further, in the nickel-based WC alloy powder of step (2), the rare earth oxide is Y2O3 and La2O3 with a mass ratio of 1:1.

[0019] Further, the nickel-based WC alloy powder in step (2) is subjected to vacuum ball milling treatment by a vacuum-protected atmosphere ball mill after mixing to ensure the dispersion uniformity of the nickel-based WC alloy powder and avoid nanoparticle agglomeration; among them, the parameters of the vacuum ball milling treatment are: oxygen content ≤ 50 ppm, ball-to-material ratio 5:1, rotation speed 200 rpm, and time 2-4 h.

[0020] Further, in step (2), the parameters of the supersonic spraying are as follows: powder feeding rate is 20 - 30 g / min, spraying pressure is 2 - 5 MPa, propane flow rate is 300 - 400 L / h, oxygen flow rate is 800 - 1000 L / h, spraying speed is 800 - 1200 m / s, spraying distance is 100 - 200 mm, and layer thickness is 0.5 - 0.8 mm. Under these process parameters, supersonic spraying can refine WC particles under the impact of high-speed gas flow. The average particle size of the refined WC particles reaches 0.5 - 1 μm. The refined WC particles can promote the uniform distribution of the coating hardness, reduce the inconsistent wear amount, and avoid the formation of orange peel-like oxide layers in high and low temperature environments. And during the spraying process, micron-sized WC preferentially deposits to form a skeleton structure, and nano-sized WC fills the gaps in the skeleton, forming mechanical interlocks through high-speed impact, thereby improving the densification and hardness of the coating after supersonic spraying.

[0021] Further, in step (3), the parameters of the ultra-high-speed laser remelting treatment are as follows: laser power is 6 - 8 kW, scanning speed is 20 - 30 m / min, spot diameter is 3 - 5 mm, shielding gas: argon, gas flow: 15 - 20 L / min, shielding gas nozzle: central shielding gas + annular shielding gas, and the laser scanning path adopts a spiral scanning method with an offset of 0.2 - 0.3 mm.

[0022] During the ultra-high-speed laser remelting process, the coating after supersonic spraying is subjected to ultra-high-speed laser remelting treatment. The high energy density of the laser melts the coating. By controlling the above laser parameters, the depth of the molten pool is 1.1 - 1.5 times the thickness of the sprayed coating, ensuring that nano-sized WC is completely dissolved in the molten pool, and a W - C - Fe diffusion layer (thickness 5 - 10 μm) is formed at the interface, achieving metallurgical bonding with the substrate, and the bonding strength ≥ 420 MPa; while micron-sized WC partially dissolves and precipitates WC / W2C hard phases, and the remaining unmelted particles serve as wear-resistant reinforcement phases to ensure that the coating hardness does not decrease.

[0023] During the remelting process, due to the precise control of the laser energy, the bonding strength between the coating and the substrate can reach more than 400 Mpa, effectively solving the problem of low physical bonding strength (<100 Mpa) between supersonic spraying and the substrate, and avoiding the phenomenon that the coating is prone to peeling under the periodic high pressure of high-temperature glass solution during high and low temperature alternating operations.

[0024] At the same time, the cooling rate of the ultra-high-speed laser remelting > 10 6 K / s. Laser remelting can improve the densification of the coating, solve the densification problem of the supersonic spraying coating, and the coating after laser remelting has almost no cracks and pores.

[0025] Compared with induction hot remelting and flame remelting, the ultra-high speed laser remelting process of the present invention is stable, the temperature and heating time can be precisely controlled, greatly reducing the defective rate and meeting the needs of automated production, thus improving both production volume and quality. Through the digital closed-loop control of laser parameters, the temperature deviation is < ±10 °C and the defective rate is < 0.5%, suitable for automated production lines (efficiency ≥ 20 pieces / hour), and the overall process stability is stronger.

[0026] Further, in step (4), the cooling rate of air cooling is controlled at 5 - 15 °C / s to avoid excessive internal stress in the substrate due to too fast cooling rate.

[0027] Through the supersonic spraying and ultra-high speed laser remelting composite process of the present invention, a uniform microstructure can be formed on the coating surface, obtaining a coating with good surface roughness. After remelting, the surface roughness Ra ≤ 1.6 μm and the porosity < 0.1%, which can be directly ground and polished to below Ra 0.4 μm, eliminating the turning process, improving production efficiency and saving costs.

[0028] As described above, a method for preparing a nickel-based WC alloy coating on the surface of a glass mold punch of the present invention has the following beneficial effects: The present invention uses the supersonic spraying and ultra-high speed laser remelting composite process to prepare a nickel-based WC alloy coating on the surface of a glass mold punch. On the one hand, by optimizing the powder design, a bimodal gradient powder composed of nano-scale WC powder and micron-scale WC powder forms a mechanical interlocking framework, and rare earth oxides are doped. Through the vacuum ball milling process, nanoparticle agglomeration is inhibited, the formation of coarse grains is suppressed, the densification of the cladding layer is improved, and cracks, pores and impurity defects in the cladding layer are effectively reduced. On the other hand, the present invention controls the process parameters of supersonic spraying and ultra-high speed laser remelting to ensure that nano-scale WC is completely dissolved in the molten pool, a W-C-Fe diffusion layer is formed at the interface, and micron-scale WC partially dissolves and precipitates WC / W2C hard phases, and the residual unmelted particles serve as wear-resistant reinforcement phases, ensuring that the coating hardness does not decrease, thereby improving the densification and hardness of the coating, accelerating phase dissolution and morphology optimization, achieving increased hardness, reduced defects, increased bonding strength and antioxidant properties, significantly improving the coating performance and production efficiency, and achieving the production goals of high efficiency, high quality and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the process flow chart of the present invention.

[0030] Figure 2 It is the metallographic microhardness detection diagram of the coating after supersonic spraying in Example 1 of the present invention.

[0031] Figure 3 It is the metallographic microhardness detection diagram of the coating prepared in Example 1 of the present invention.

[0032] Figure 4 This is the metallographic diagram of the coating prepared in Comparative Example 1 of the present invention.

[0033] Figure 5 This is the metallographic microhardness test diagram of the coating prepared in Comparative Example 1 of the present invention. Specific Embodiments

[0034] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0035] Example 1

[0036] A method for preparing a nickel-based WC alloy coating on the surface of a glass mold punch includes the following steps:

[0037] (1) Substrate pretreatment:

[0038] Take a substrate of a glass mold punch, first ultrasonically clean it with acetone for 20 minutes, then polish it with sandpaper to Ra 1.0 μm, and then preheat it at 150 °C for 8 minutes;

[0039] (2) Supersonic spraying of nickel-based WC alloy coating:

[0040] After uniformly mixing nano-scale WC powder and micro-scale WC powder according to a mass ratio of 3:7, prepare nickel-based WC alloy powder. The nickel-based WC alloy powder includes the following components by mass percentage: B: 1.2%, Co: 4%, Cr: 7.2%, Fe: 2.0%, Si: 2.2%, WC: 30%, Y2O3 and La2O3 with a mass ratio of 1:1: 1.0%, and the balance is Ni; ball mill the prepared nickel-based WC alloy powder for 4 hours under the conditions of a rotation speed of 200 r / min and a ball-to-material ratio of 5:1;

[0041] Use the ball-milled nickel-based WC alloy powder and spray it on the substrate of the glass mold punch by a supersonic spraying device to prepare a nickel-based WC alloy coating, and then detect the coating; the parameters of the supersonic spraying are: the powder feeding rate is 25 g / min, the spraying pressure is set at 3 MPa, the propane flow rate is 300 L / h, the oxygen flow rate is 900 L / h, the spraying speed is 1000 m / s, and the spraying distance is 150 mm;

[0042] (3) Ultra-high-speed laser remelting treatment:

[0043] The nickel-based WC alloy coating prepared in step (2) is remelted using an ultra-high-speed laser remelting device. The laser power is 6 kW, the scanning speed is 20 m / min, the spot diameter is 3 mm, the protective gas is argon, the gas flow is 20 L / min, the protective gas nozzle is a central protective gas + annular protective gas, and the laser scanning path adopts a spiral scanning method with an offset of 0.3 mm;

[0044] (4) Post-treatment:

[0045] The coating after ultra-high-speed laser remelting treatment is air-cooled with a cooling rate of 10 °C / s, and then inspected.

[0046] The inspection results are as Figure 2 and Figure 3 shown. Figure 2 is the metallographic microhardness inspection diagram of the coating after supersonic spraying in step (2). It can be seen that the WC particles in the coating are fine after supersonic spraying, the coating hardness is uniform, but there are more pores and the compactness in the coating is poor. The black dots in the figure are pores, the WC particles are fine but unevenly distributed. Figure 3 is the inspection diagram of the coating after ultra-high-speed laser remelting treatment and air-cooling in step (4). It can be seen that for the metallographic microhardness inspection of the coating after high-speed laser remelting, there are no coarse WC particles, the coating is dense and pore-free, the hardness distribution is uniform, and the average hardness is HRC59.1.

[0047] Example 2

[0048] A method for preparing a nickel-based WC alloy coating on the surface of a glass mold punch, comprising the following steps:

[0049] (1) Substrate pretreatment:

[0050] Take a glass mold punch substrate, first ultrasonically clean it with alcohol for 10 minutes, then polish it with sandpaper to Ra 0.8 μm, and then preheat it at 100 °C for 15 minutes;

[0051] (2) Supersonic spraying of nickel-based WC alloy coating:

[0052] After mixing nano-scale WC powder and micro-scale WC powder evenly according to a mass ratio of 5:5, nickel-based WC alloy powder is prepared. The nickel-based WC alloy powder includes the following components by mass percentage: B: 1.0%, Co: 4.2%, Cr: 7.5%, Fe: 2.2%, Si: 2.5%, WC: 35%, Y2O3 and La2O3 with a mass ratio of 1:1: 1.0%, and the balance Ni; The prepared nickel-based WC alloy powder is ball-milled for 2 hours under the conditions of a rotation speed of 200 r / min and a ball-to-material ratio of 5:1;

[0053] Using the nickel-based WC alloy powder after ball milling, the substrate of the glass mold punch is sprayed with a supersonic spraying device to prepare a nickel-based WC alloy coating, and then the coating is detected; the parameters of the supersonic spraying are as follows: the powder feeding rate is 20 g / min, the spraying pressure is set at 2 MPa, the propane flow rate is 300 L / h, the oxygen flow rate is 1000 L / h, the spraying speed is 1200 m / s, and the spraying distance is 200 mm;

[0054] (3) Ultra-high-speed laser remelting treatment:

[0055] The nickel-based WC alloy coating prepared in step (2) is remelted with an ultra-high-speed laser remelting device. The laser power is 8 kW, the scanning speed is 30 m / min, the spot diameter is 5 mm, the shielding gas: argon, the gas flow: 20 L / min, the shielding gas nozzle: central shielding gas + annular shielding gas, and the scanning path of the laser adopts a spiral scanning method with an offset of 0.2 mm;

[0056] (4) Post-treatment:

[0057] The coating after ultra-high-speed laser remelting treatment is air-cooled, and the cooling rate is 15 °C / s.

[0058] Comparative Example 1

[0059] A preparation method for a nickel-based WC alloy coating on the surface of a glass mold punch, comprising the following steps:

[0060] (1) Substrate pretreatment:

[0061] Take a substrate of a glass mold punch, first ultrasonically clean it with acetone for 20 minutes, then polish it with sandpaper to Ra 1.0 μm, and then preheat it at 150 °C for 8 minutes;

[0062] (2) Conventional laser cladding nickel-based WC alloy cladding layer:

[0063] After mixing nano-scale WC powder and micro-scale WC powder evenly according to a mass ratio of 3:7, nickel-based WC alloy powder is prepared. The nickel-based WC alloy powder includes the following components by mass percentage: B: 1.2%, Co: 4%, Cr: 7.2%, Fe: 2.0%, Si: 2.2%, WC: 30%, Y2O3 and La2O3 with a mass ratio of 1:1: 1.0%, and the balance is Ni; the prepared nickel-based WC alloy powder is ball milled for 4 hours under the conditions of a rotation speed of 200 r / min and a ball-to-material ratio of 5:1;

[0064] Using the nickel-based WC alloy powder after ball milling, a nickel-based WC alloy cladding layer is prepared on the surface of the glass mold punch substrate by a conventional laser cladding process, and then detection is carried out.

[0065] The test results are as Figure 4 andFigure 5 As shown Figure 4 is the metallographic diagram of the prepared cladding layer. It can be seen that relatively large spherical WC particles are distributed in the cladding layer. Figure 5 is the metallographic microhardness detection diagram of the cladding layer. It can be seen that the hardness inside the spherical WC particles reaches HRC 63.2, and the hardness in the non-spherical WC region is about HRC 45. The large hardness difference and uneven distribution will lead to uneven wear and cause the orange peel oxidation phenomenon.

[0066] Comparative Example 2

[0067] A preparation method for a nickel-based WC alloy coating on the surface of a glass mold punch includes the following steps:

[0068] (1) Substrate pretreatment:

[0069] Take a glass mold punch substrate, first ultrasonically clean it with acetone for 20 minutes, then polish it with sandpaper to Ra1.0μm, and then preheat it at 150°C for 8 minutes;

[0070] (2) Supersonic spraying of nickel-based WC alloy coating:

[0071] After mixing nano-sized WC powder and micro-sized WC powder evenly by a mass ratio of 3:7, prepare nickel-based WC alloy powder. The nickel-based WC alloy powder includes the following components by mass percentage: B: 1.2%, Co: 4%, Cr: 7.2%, Fe: 2.0%, Si: 2.2%, WC: 30%, Y2O3 and La2O3 with a mass ratio of 1:1: 1.0%, and the balance is Ni; Ball mill the prepared nickel-based WC alloy powder for 4 hours under the conditions of a rotation speed of 200 r / min and a ball-to-material ratio of 5:1;

[0072] Use the ball-milled nickel-based WC alloy powder and spray it on the glass mold punch substrate with a supersonic spraying device to prepare a nickel-based WC alloy coating, and then detect the coating; The parameters of supersonic spraying are: powder feeding rate is 25 g / min, spraying pressure is set at 3 MPa, propane flow rate is 300 L / h, oxygen flow rate is 900 L / h, spraying speed is 1000 m / s, and spraying distance is 150 mm;

[0073] (3) Induction heat remelting treatment:

[0074] Use an induction heat remelting device to remelt the nickel-based WC alloy coating prepared in step (2), and air-cool the coating after induction heat remelting treatment, with a cooling rate of 10°C / s.

[0075] The coatings prepared in Example 1 and Comparative Examples 1 and 2 were tested, and the test results are shown in Table 1. It can be seen that the nickel-based WC alloy coating of the glass mold punch prepared by the present invention exhibits good performance in terms of bonding strength, hardness distribution uniformity, density, surface roughness, etc. Compared with the coatings prepared by traditional laser cladding coatings and induction thermogravimetric remelting processes, the coating of the present invention has significant advantages in terms of bonding strength, wear amount consistency, antioxidant performance, production automation degree, and production efficiency.

[0076] Table 1. Test Results of Example 1 and Comparative Examples 1 and 2

[0077]

[0078]

[0079] In summary, the present invention uses a process of combining supersonic spraying and ultra-high-speed laser remelting to prepare a nickel-based WC alloy coating on the surface of a glass mold punch. On the one hand, by optimizing the powder design, a bimodal gradient powder composed of nano-scale WC powder and micro-scale WC powder is used to form a mechanical interlocking skeleton, and rare earth oxides are doped. The vacuum ball milling process is used to inhibit the agglomeration of nano-particles, inhibit the formation of coarse grains, improve the density of the clad layer, and effectively reduce cracks, pores, and impurity defects in the clad layer. On the other hand, the present invention controls the process parameters of supersonic spraying and ultra-high-speed laser remelting to ensure that nano-scale WC is completely dissolved in the molten pool, and a W-C-Fe diffusion layer is formed at the interface. After partial dissolution of micro-scale WC, WC / W2C hard phases are precipitated, and the remaining unmelted particles serve as wear-resistant reinforcement phases to ensure that the hardness of the coating does not decrease. Thus, the density and hardness of the coating after supersonic spraying are improved, the phase dissolution and morphology optimization are accelerated, the hardness is increased, the defects are reduced, the bonding strength and antioxidant characteristics are increased, and the performance and production efficiency of the coating are significantly improved, achieving the production goals of high efficiency, high quality, and energy saving. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0080] Among them, the terms such as "upper", "lower", "left", "right", "front", "rear", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0081] The above embodiments are only illustrative of the principles and effects of the present invention and are not used to limit the present invention. All equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A preparation method for a nickel-based WC alloy coating on the surface of a glass mold punch, characterized in that, It includes the following steps: (1) Pretreat the substrate; (2) Prepare a nickel-based WC alloy coating on the surface of the substrate by supersonic spraying. The powder used is nickel-based WC alloy powder, and the nickel-based WC alloy powder includes the following components by mass percentage: B: 1-1.2%, Co: 3.8-4.2%, Cr: 6.8-7.5%, Fe: 1.8-2.2%, Si: 2.0-2.5%, WC: 30-35%, rare earth oxide: 0.5-1.0%, and the balance is Ni; (3) Perform ultra-high-speed laser remelting treatment on the nickel-based WC alloy coating in step (2); (4) Air-cool the coating after ultra-high-speed laser remelting treatment.

2. The preparation method according to claim 1, characterized in that, In step (1), the pretreatment includes substrate surface cleaning and substrate preheating.

3. The preparation method according to claim 1, wherein, In the nickel-based WC alloy powder of step (2), WC is a bimodal gradient composite powder of nano-scale WC and micro-scale WC. Among them, the size range of nano-scale WC is 300-500 nm, and the content is 30-50 wt%; the size range of micro-scale WC is 15-35 μm, and the content is 50-70 wt%.

4. The preparation method according to claim 1, wherein, In the nickel-based WC alloy powder of step (2), the rare earth oxide is Y2O3 and La2O3 with a mass ratio of 1:

1.

5. The preparation method according to claim 1, characterized in that, The nickel-based WC alloy powder in step (2) is subjected to vacuum ball milling treatment by a vacuum protective atmosphere ball mill after mixing. The parameters of the vacuum ball milling treatment are: oxygen content ≤ 50 ppm, ball-to-powder ratio 5:1, rotation speed 200 rpm, and time 2-4 h.

6. The preparation method according to claim 1, characterized in that, In step (2), the parameters of supersonic spraying are: powder feeding rate 20-30 g / min, spraying pressure 2-5 MPa, propane flow rate 300-400 L / h, oxygen flow rate 800-1000 L / h, spraying speed 800-1200 m / s, spraying distance 100-200 mm, and layer thickness 0.5-0.8 mm.

7. The preparation method according to claim 1, characterized in that, In step (3), the parameters of ultra-high-speed laser remelting treatment are: laser power 6-8 kW, scanning speed 20-30 m / min, spot diameter 3-5 mm, protective gas: argon, gas flow: 15-20 L / min, protective gas nozzle: central protective gas + annular protective gas, and the laser scanning path adopts a spiral scanning method with an offset of 0.2-0.3 mm.

8. The preparation method according to claim 7, wherein The molten pool depth is 1.1-1.5 times the thickness of the sprayed coating.

9. The preparation method according to claim 7, wherein The surface roughness Ra of the coating after ultra-high-speed laser remelting treatment is ≤ 1.6 μm, and the porosity is < 0.1%.

10. The preparation method according to claim 1, wherein In step (4), the cooling rate of air cooling is controlled at 5-15 °C / s.

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