Hot-rolled descaling roller surface wc65 composite coating and method for preparing the same

Abstract

The application provides a WC65 composite coating on the surface of a hot-rolling descaling roller and a preparation method thereof. The coating comprises a Ni45 transition layer deposited on the surface of the hot-rolling descaling roller base body and a working layer sprayed on the surface of the Ni45 transition layer. The preparation method comprises the following steps: depositing Ni45 powder on the surface of the hot-rolling descaling roller base body to form a Ni45 transition layer, and spraying a mixture of WC65 powder and FeCoNiCrMn powder on the surface of the Ni45 transition layer. The hot-rolling descaling roller provided by the application has the advantages of stable friction coefficient, good wear resistance and high hardness, and the coating surface is almost free of peeling defects and furrow defects, and the coating surface is also rarely attached with oxidized particles.

Description

Technical Field

[0001] This invention belongs to the field of hot-rolled descaling roll protection technology, specifically relating to a WC65 composite coating on the surface of a hot-rolled descaling roll and its preparation method. Background Technology

[0002] In the steel rolling process, descaling rolls are crucial mechanical equipment and a key component of the descaling box. During descaling, the descaling rolls come into direct contact with the high-temperature, high-speed moving slab. After a period of use, descaling rolls often suffer from surface cracks, pits, and fissures due to frictional wear, thermal fatigue, and high-pressure water erosion, ultimately leading to their scrapping. Because the actual working environment of descaling rolls is extremely harsh, with operating temperatures reaching up to 600℃ and direct exposure to high-temperature metal surfaces, this high-temperature environment places high demands on the stability and heat resistance of the descaling rolls. In addition to high temperatures, descaling rolls are also subjected to the impact and corrosion of high-pressure water on the production line. After working in such a harsh environment for a period of time, descaling rolls will exhibit varying degrees and forms of damage, typically manifesting as surface pits, surface cracks, and localized peeling. Descaling rolls must withstand strong friction and pressure to remove scale and dirt from metal surfaces, which leads to surface wear and fatigue failure, affecting performance and lifespan. Currently, the main solution is to apply a coating to the surface of the descaling roll to ensure its performance and lifespan.

[0003] In existing solutions, document CN110004372B discloses a high-temperature resistant, oxidation-resistant, and wear-resistant metallurgical roller, comprising a substrate and a composite coating. The substrate is carbon structural steel, with the following mass percentages of elements: C: 0.11-0.15%, Al: 0.035-0.08%, Mn: 0.32-0.63%, S: 0.008-0.016%, P: 0.012-0.027%, Si: 0.06-0.15%, N: 0.001-0.003%, Als: 0.011-0.052%, Fe: 98.69-99.18%. The composite coating is made from alloy powder. This solution improves the microstructure density, reduces cracking tendency, and extends the service life of the metallurgical roller by reducing the coating porosity to below 0.3%. However, the proposed solution does not address the furrowing phenomenon that occurs when the descaling roller is used in high-temperature environments.

[0004] In addition, descaling rollers are prone to oxidation particles when used in high-temperature environments. How to effectively remove these oxidation particles from the descaling rollers is also a problem that needs to be solved. Summary of the Invention

[0005] To address at least the problems mentioned in the background art, the present invention provides a WC65 composite coating on the surface of a hot-rolled descaling roll and a method for preparing the same.

[0006] The present invention adopts the following technical solution.

[0007] A WC65 composite coating for the surface of a hot-rolled descaling roll includes a Ni45 transition layer welded onto the surface of the hot-rolled descaling roll substrate, and a working layer sprayed onto the surface of the Ni45 transition layer. The mass ratio of WC65 powder to FeCoNiCrMn powder in the raw material of the working layer is 6~8:2~4. Of which, by mass percentage, The composition of the Ni45 transition layer is: C: 0.2-0.6%, B: 2-3%, Si: 3-4.5%, Cr: 7-12%, Fe: <15%, Mn: <0.1%, with the balance being nickel and unavoidable impurities; The composition of WC65 powder is: W: 95-96%, C: 3.8-4.1%, Ti: <0.1%, Si: <0.02%, Fe: <0.5%, Vi: <0.05%, with the balance being unavoidable impurities; The composition of FeCoNiCrMn powder is: Fe: 20%, Co: 20%, Ni: 20%, Cr: 20%, Mn: 20%, with the balance being unavoidable impurities.

[0008] As a preferred option, the mass ratio of WC65 powder to FeCoNiCrMn powder in the raw materials of the working layer is 7:3.

[0009] As a preferred option, the particle size of the raw material powder, WC65 powder, and FeCoNiCrMn powder for the Ni45 transition layer is 45-150 μm.

[0010] As a preferred embodiment, the Ni45 transition layer thickness is 4±0.5mm and the working layer thickness is 3±0.5mm.

[0011] As a preferred embodiment, the composition of the Ni45 transition layer is: C: 0.3±0.05%, B: 2.5±0.05%, Si: 3.5±0.05%, Cr: 8±0.1%, Fe: 9±1%, Mn: <0.1%, with the balance being nickel and unavoidable impurities.

[0012] A method for preparing the aforementioned WC65 composite coating on the surface of a hot-rolled descaling roll includes the following steps: Step 1, Pre-treatment: Clean the surface of the 45# steel alloy hot-rolled descaling roll substrate, and then perform ultrasonic cleaning. Step 2, prepare Ni45 powder; Step 3: Ni45 powder is deposited onto the surface of the hot-rolled descaling roll substrate to form a Ni45 transition layer; Step 4: After step 3 is completed, place the workpiece in the air to cool for three days; Step 5: Prepare the working layer powder by mixing WC65 powder and FeCoNiCrMn powder at a mass ratio of 7:3 to obtain a mixed powder. Step 6: Spray the working layer onto the surface of the Ni45 transition layer of the obtained workpiece, and then remove the workpiece. Step 7: Post-process the obtained workpiece. The post-processing procedure is as follows: subject the workpiece surface to sliding friction treatment for 30 minutes under the conditions of "400℃, 15N, 17Hz" or "600℃, 15N, 13Hz" to obtain the descaling roller.

[0013] Furthermore, step 3 specifically includes: First, program the industrial robot to determine the working route, adjust the distance between the plasma spray gun and the workpiece of the ion spraying system to 10-15 mm, and set the plasma spray gun speed to 220 mm / min. Then, Ni45 powder was placed into the powder feeder and the powder feeding rate was set to 16.5 g / min, and the working current was set to 140A. Next, the industrial robot is started to spray the preheated workpiece. After the first run of the industrial robot is completed and it returns to the initial position, the residual powder in the powder feeder is cleaned. Then, NI45 powder is added to the powder feeder and the industrial robot is started again. After the second run is completed, the powder feeder is cleaned again.

[0014] Furthermore, step 6 specifically includes: First, program the industrial robot to determine the working route, adjust the distance between the plasma spray gun and the workpiece of the ion spraying system to 10-15 mm, and set the plasma spray gun speed to 200 mm / min. Then, the mixed powder is placed into the powder feeder and the powder feeding rate is set to 15.5 g / min, and the working current is set to 140A; Next, the industrial robot is started to spray the preheated workpiece. After the first run of the industrial robot is completed and it returns to the initial position, the residual powder in the powder feeder is cleaned. Then, mixed powder is added again to the powder feeder and the industrial robot is started again. After the second run is completed, the powder feeder is cleaned again.

[0015] As a preferred embodiment, the workpiece is preheated to 300°C in step 3 and to 400°C in step 6.

[0016] Beneficial effects: The hot-rolled descaling roller provided by the present invention not only has the advantages of stable friction coefficient, good wear resistance and high hardness, but also has almost no peeling defects and no ploughing defects on its coating surface, and very few oxide particles attached to the coating surface. It cleverly solves the technical problem that oxide particles are easy to appear in the descaling roller during use in high temperature environment. Attached Figure Description

[0017] Figure 1 The friction coefficient curve (200°C) of the descaling roller sample in the example is shown. Figure 2 The friction coefficient curve (400℃) of the descaling roller sample in the example is shown. Figure 3 The friction coefficient curve (600℃) of the descaling roller sample in the example is shown. Figures 4-17 The microstructure of the descaling roller sample surface in the embodiments is shown in the figures. Parts (b) and (c) correspond to different magnifications, as detailed in the lower left corner of the figures. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0019] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, comprising the following steps: Step 1, Pre-treatment: Grind the 45# steel high-temperature alloy roller substrate to clean the cutting marks and oxide film generated by the surface wire cutting, and then use ultrasonic cleaning to remove surface oil. Step 2: Prepare Ni45 powder / powder. Ni45 powder produced by Zigong Great Wall Surface Engineering Technology Co., Ltd. has a particle size of 45-150μm. Step 3: Ni45 powder is deposited onto the surface of the hot-rolled descaling roll substrate to form a Ni45 transition layer. Specifically: The spraying equipment uses the DML-V03CD plasma spraying system. Turn on the main control power, turn on the welding machine power, turn on the cooling circulating water and air supply device, select continuous welding mode, set the powder feed rate to 40g, adjust the welding current to 140A, and set the rise time (the time required for the base value to reach the welding current) to 0.3s. The powder feed gas flow rate is 4L / min, the ion gas flow rate is 2L / min, and the shielding gas flow rate is 10L / min. During surfacing, first preheat the roller substrate to 300℃, then program the industrial robot to determine the working path, adjust the distance between the plasma spray gun and the workpiece to 12 mm, and set the plasma spray gun speed to 220 mm / min. Then, load Ni45 powder / powder into the powder feeder. Next, unscrew the powder feeder nut, place the funnel, and add Ni45 powder / powder. Note that the amount of powder added should not exceed the top of the air pipe inside the powder hopper. After loading the powder, remove the funnel, place the nut, and tighten it to prevent air leakage. Then, set the powder feeding rate to 16.5. g / min; Next, fine-tune the working parameters and start the industrial robot to begin spraying. After the industrial robot finishes its first run and returns to its initial position, clean the residual powder in the powder feeder. Then, add NI45 powder to the powder feeder and start the industrial robot again. After the second run is completed, clean the powder feeder again and remove the workpiece. Step 4: After step 3 is completed, place the workpiece in air at room temperature to cool for three days. Step 5: Prepare the working layer powder by mixing WC65 powder and FeCoNiCrMn powder at a mass ratio of 7:3 to obtain a mixed powder. Step 6: Spray the working layer onto the surface of the Ni45 transition layer of the obtained workpiece, and then remove the workpiece. Specifically: the air-cooled workpiece was preheated to 400℃, the industrial robot was reprogrammed to determine the working route, the distance between the plasma spray gun and the workpiece was adjusted to 12 mm, and the plasma spray gun speed was set to 200 mm / min; the mixed powder was placed in the powder feeder, the powder feeding rate was set to 15.5 g / min, and the current was set to 140 A; then, the industrial robot was started to begin spraying. After the industrial robot finished its first run and returned to its initial position, the residual powder in the powder feeder was cleaned; then, the mixed powder was added again to the powder feeder and the industrial robot was started again. After the second run was completed, the powder feeder was cleaned again, the workpiece was removed, and the resulting Ni45 transition layer thickness was 4 mm and the working layer thickness was 3 mm; Step 7: Post-process the obtained workpiece. The post-processing procedure is as follows: the entire surface of the workpiece is subjected to sliding friction treatment for 30 minutes under the conditions of "400℃, 15N, 17Hz". The sliding direction during the sliding friction process is along the axial direction of the workpiece to obtain the descaling roller.

[0020] The descaling roller sample prepared in this embodiment was subjected to performance testing and microscopic inspection. The results showed that the hardness was 701 HV and the coefficient of friction (approximately 0.4) was as follows: Figure 2 The corresponding curve (400C-15N-17Hz) and microstructure diagram are shown below. Figure 11 It shows no peeling defects, no furrow defects, and very few attached oxide particles. Example

[0021] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 600℃, 15N, and 13Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 699HV and a coefficient of friction (approximately 0.1). Figure 3 The corresponding curve (600C-15N-13Hz) and microstructure diagram are shown below. Figure 15 It shows no peeling defects and very few attached oxide particles. Example

[0022] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment for 30 minutes under conditions of 200℃, 10N, and 15Hz to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 640 HV and a coefficient of friction (approximately 0.1~0.3). Figure 1 The corresponding curve (200C-10N-15Hz) and the microstructure diagram are shown below. Figure 4 The results show that there are a large number of attached oxide particles, which are in the form of loose clusters and honeycomb shapes. Example

[0023] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment for 30 minutes under conditions of 200℃, 15N, and 13Hz to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed that the hardness was 640HV, and the coefficient of friction (approximately 0.1~0.15) was as follows: Figure 1 The corresponding curve (200C-15N-13Hz) and microstructure diagram are shown below. Figure 5 It shows ploughing defects, with a large number of attached oxide particles in a loose, clustered manner. Example

[0024] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 200℃, 15N, and 15Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 635HV and a coefficient of friction (approximately 0.08~0.15). Figure 1 The corresponding curve (200C-15N-15Hz) and the microstructure diagram are shown below. Figure 6 It shows furrow defects and multiple spalling defects, with oxide particles visible within the spalling defects. Example

[0025] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 200℃, 15N, and 17Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed that the hardness was 642HV, and the coefficient of friction (approximately 0.4~0.6) was as follows: Figure 1 The corresponding curve (200C-15N-17Hz) and microstructure diagram are shown below. Figure 7 It shows a large number of oxide particles aggregated in clumps. Example

[0026] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 400℃, 10N, and 15Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed that the hardness was 700 HV, and the coefficient of friction (approximately 0.1~0.15) was as follows: Figure 2 The corresponding curve (400C-10N-15Hz) and microstructure diagram are shown below. Figure 8 It shows multiple long, strip-shaped furrow defects and spalling defects. Example

[0027] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 400℃, 15N, and 13Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 698HV and a coefficient of friction (approximately 0.1~0.15). Figure 2 The corresponding curve (400C-15N-13Hz) and microstructure diagram are shown below. Figure 9 It shows a large number of oxide particles. Example

[0028] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 400℃, 15N, and 15Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 699HV and a coefficient of friction (approximately 0.1~0.15). Figure 2 The corresponding curve (400C-15N-15Hz) and microstructure diagram are shown below. Figure 10 It shows furrow defects, spalling defects, and light white patches (defects that are about to spall off), with oxide particles visible within the spalling defects. Example

[0029] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 600℃, 10N, and 13Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 695HV, and the microstructure diagram is shown below. Figure 12 It shows ploughing defects, peeling defects, and a lot of oxide particles. Example

[0030] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 600℃, 10N, and 15Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 696HV and a coefficient of friction (approximately 0.05~0.15). Figure 3The corresponding curve (600C-10N-15Hz) and microstructure diagram are shown below. Figure 13 It shows furrow defects and fewer oxide particles. Example

[0031] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 600℃, 10N, and 17Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 694HV and a coefficient of friction (approximately 0.05~0.15). Figure 3 The corresponding curve (600C-10N-17Hz) and microstructure diagram are shown below. Figure 14 It shows furrow defects and large areas of oxide particles. Example

[0032] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 600℃, 15N, and 15Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 696HV and a coefficient of friction (approximately 0.05~0.2). Figure 3 The corresponding curve (600C-15N-15Hz) and microstructure diagram are shown below. Figure 16 It shows furrow defects, multiple spalling defects, and many oxide particles attached, some of which are found within the spalling defects. Example

[0033] A method for preparing a WC65 composite coating on the surface of a hot-rolled descaling roll, referring to Example 1, differs from Example 1 in step 7, where the obtained workpiece undergoes post-processing. The post-processing step involves subjecting the entire surface of the workpiece to sliding friction treatment at 600℃, 15N, and 17Hz for 30 minutes to obtain the descaling roll. Performance tests and microscopic examinations were performed on the descaling roll sample obtained in this example. The results showed a hardness of 692HV and a coefficient of friction (approximately 0.05~0.15). Figure 3 The corresponding curve (600C-15N-17Hz) and microstructure diagram are shown below. Figure 16 It shows furrow defects and large-area spalling defects, with many oxide particles attached, some of which are found within the spalling defects.

[0034] The hot-rolled descaling rolls provided in Examples 1-2 not only have the advantages of stable friction coefficient, good wear resistance and high hardness, but also have almost no peeling defects or furrow defects on their coating surface, and very few oxide particles attached to the coating surface. This cleverly solves the technical problem that descaling rolls are prone to oxide particles when used in high-temperature environments.

Claims

1. A WC65 composite coating on the surface of a hot-rolled descaling roll, characterized in that, It includes a Ni45 transition layer welded onto the surface of the hot-rolled descaling roll substrate, and a working layer sprayed onto the surface of the Ni45 transition layer. The mass ratio of WC65 powder to FeCoNiCrMn powder in the raw material of the working layer is 6~8:2~4. Of which, by mass percentage, The composition of the Ni45 transition layer is: C: 0.2-0.6%, B: 2-3%, Si: 3-4.5%, Cr: 7-12%, Fe: <15%, Mn: <0.1%, with the balance being nickel and unavoidable impurities; The composition of WC65 powder is: W: 95-96%, C: 3.8-4.1%, Ti: <0.1%, Si: <0.02%, Fe: <0.5%, Vi: <0.05%, with the balance being unavoidable impurities; The composition of FeCoNiCrMn powder is: Fe: 20%, Co: 20%, Ni: 20%, Cr: 20%, Mn: 20%; The method for preparing the WC65 composite coating on the surface of the hot-rolled descaling roll includes: Step 1, Pre-treatment: Clean the surface of the 45# steel alloy hot-rolled descaling roll substrate, and then perform ultrasonic cleaning. Step 2, prepare Ni45 powder; Step 3: Ni45 powder is deposited onto the surface of the hot-rolled descaling roll substrate to form a Ni45 transition layer; Step 4: After step 3 is completed, place the workpiece in the air to cool for three days; Step 5: Prepare the working layer powder by mixing WC65 powder and FeCoNiCrMn powder in a certain proportion to obtain a mixed powder. Step 6: Spray the working layer onto the surface of the Ni45 transition layer of the obtained workpiece, and then remove the workpiece. Step 7: Post-process the obtained workpiece. The post-processing procedure is as follows: subject the workpiece surface to sliding friction treatment for 30 minutes under the conditions of "400℃, 15N, 17Hz" or "600℃, 15N, 13Hz" to obtain the descaling roller.

2. The WC65 composite coating on the surface of the hot-rolled descaling roll according to claim 1, characterized in that: The mass ratio of WC65 powder to FeCoNiCrMn powder in the raw materials of the working layer is 7:

3.

3. The WC65 composite coating on the surface of the hot-rolled descaling roll according to claim 2, characterized in that: The particle sizes of the raw material powder, WC65 powder, and FeCoNiCrMn powder for the Ni45 transition layer are all 45-150 μm.

4. The WC65 composite coating on the surface of the hot-rolled descaling roll according to claim 3, characterized in that: The Ni45 transition layer thickness is 4±0.5mm, and the working layer thickness is 3±0.5mm.

5. The WC65 composite coating on the surface of the hot-rolled descaling roll according to any one of claims 1-4, characterized in that, The composition of the Ni45 transition layer is: C: 0.3±0.05%, B: 2.5±0.05%, Si: 3.5±0.05%, Cr: 8±0.1%, Fe: 9±1%, Mn: <0.1%, with the balance being nickel and unavoidable impurities.

6. The WC65 composite coating on the surface of the hot-rolled descaling roll according to claim 1, characterized in that, Step 3 specifically includes: First, program the industrial robot to determine the working route, adjust the distance between the plasma spray gun and the workpiece of the ion spraying system to 10-15 mm, and set the plasma spray gun speed to 220 mm / min. Then, Ni45 powder was placed into the powder feeder and the powder feeding rate was set to 16.5 g / min, and the working current was set to 140 A. Next, the industrial robot is started to spray the preheated workpiece. After the first run of the industrial robot is completed and it returns to the initial position, the residual powder in the powder feeder is cleaned. Then, NI45 powder is added to the powder feeder and the industrial robot is started again. After the second run is completed, the powder feeder is cleaned again.

7. The WC65 composite coating on the surface of the hot-rolled descaling roll according to claim 6, characterized in that, Step 6 specifically includes: First, program the industrial robot to determine the working route, adjust the distance between the plasma spray gun and the workpiece of the ion spraying system to 10-15 mm, and set the plasma spray gun speed to 200 mm / min. Then, the mixed powder is placed into the powder feeder and the powder feeding rate is set to 15.5 g / min, and the working current is set to 140 A; Next, the industrial robot is started to spray the preheated workpiece. After the first run of the industrial robot is completed and it returns to the initial position, the residual powder in the powder feeder is cleaned. Then, mixed powder is added again to the powder feeder and the industrial robot is started again. After the second run is completed, the powder feeder is cleaned again.

8. The WC65 composite coating on the surface of the hot-rolled descaling roll according to claim 7, characterized in that: In step 3, the workpiece is preheated to 300°C, and in step 6, the workpiece is preheated to 400°C.

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