Coating for mowing robot cutter and preparation method thereof

Abstract

The invention provides a coating for a mowing robot cutter and a preparation method thereof.The preparation method of the coating comprises the steps that NiCrBSi powder and CrC powder are mechanically mixed to obtain brazing filler metal, and the mass of NiCrBSi accounts for 55-70% of the total mass of the brazing filler metal; then slowly adding brazing filler metal into the polyvinyl alcohol aqueous solution, uniformly stirring to obtain slurry, smearing the slurry on the cutting surface of the cutter with the thickness of 0.4-0.8 mm, and standing and drying at room temperature for 12-24 hours to obtain a cutter loaded with a coating; then the cutter loaded with the coating is baked and preheated, and heat preservation is conducted for 30 min at the temperature of 750-850 DEG C; and finally, the tool treated in the fourth step is subjected to coating braze coating through induction heating equipment, and the heating temperature is kept at 1000-1150 DEG C. The NiCrBSi-CrC coating is formed on the surface of the tool, so that the wear resistance and corrosion resistance of the tool can be improved, and the working performance of the tool is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a coating for a lawn mowing robot cutter and a preparation method thereof. Background Art

[0002] Mowing robots play an important role in my country's agriculture or fruit industry in maintaining cleanliness, promoting healthy growth of crops and improving agricultural production efficiency. The main component of a mowing robot is the cutter. The condition of the cutter greatly affects the performance of the robot. If there is a problem with the cutter, the mowing robot may not be able to operate effectively and bear a greater load during operation, which may cause excessive wear of other components, increase the frequency of maintenance and replacement, and increase safety hazards during operation, and may even cause personal injury.

[0003] During the cutting process of the mowing robot, the cutter often comes into contact with hard objects such as bricks and stones, which causes the cutter to bear a large impact force. In addition, cutting the stems and leaves of plants will also cause the cutter to rust. Especially after rusting, the structure of the blade will be damaged and the cutting ability will be significantly reduced. In order to reduce the maintenance frequency of the cutter of the mowing robot and improve the efficiency of the operation, it is urgent to improve the wear resistance and corrosion resistance of the cutter.

[0004] In order to improve the wear resistance of the lawn mowing robot tool in the prior art, it is often achieved by increasing the Mn content, but a higher Mn content will reduce the corrosion resistance of the tool. Although the corrosion resistance can be increased by increasing the content of Cr and Ni, the effect is not obvious in practical applications. The patent with publication number CN116240545A discloses a high entropy composite coating for cemented carbide tools and its preparation method. A high entropy alloy FeCoCrNiMn layer is formed on the surface of the cemented carbide tool by surfacing technology, and then a boride layer is formed on the surface of the high entropy alloy FeCoCrNiMn layer by a boriding process. The alloy layer has a high Mn content, which improves the work hardening performance, but the brittleness of the coating is greatly increased and the toughness is reduced. When encountering instantaneous impact force, the coating is easy to disintegrate or break and fail; and the corrosion resistance and other environmental adaptability, especially in a specific working environment, are not obvious. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a coating for a lawn mowing robot tool and a preparation method thereof. A layer of NiCrBSi-CrC coating is formed on the surface of the tool by brazing, which can improve the wear resistance and corrosion resistance of the tool, thereby improving the operating performance of the tool.

[0006] In order to achieve the above object, the specific scheme adopted by the present invention is: In one aspect, the present invention provides a method for preparing a coating for a lawn mowing robot tool, which mainly comprises the following steps: Step 1, preparing solder, the solder is NiCrBSi-CrC powder, which is obtained by mechanically mixing NiCrBSi powder and CrC powder, wherein the mass of NiCrBSi accounts for 55-70% of the total mass of the solder; Step 2: slowly add solder to the polyvinyl alcohol aqueous solution and stir evenly to obtain a slurry; Step 3: Apply the slurry to the cutting surface of the tool with a thickness of 0.4 to 0.8 mm, and let it stand and dry at room temperature for 12 to 24 hours to obtain a tool loaded with a coating; Step 4: preheat the coated tool at 750-850°C for 30 minutes; Step 5: Use induction heating equipment to braze the coating on the tool treated in step 4, and keep the heating temperature at 1000-1150°C.

[0007] Furthermore, in step 1, the mass fraction of each element in the NiCrBSi powder is: Cr 15-18%, B 1-2.5%, Si 1.5-2%, and the balance is Ni.

[0008] Furthermore, in step 2, the mass of the polyvinyl alcohol is 2% of the mass of the solder.

[0009] Furthermore, in step three, before applying the slurry, the tool is pretreated, and the specific method of the pretreatment is: grinding the tool surface with sandpaper of mesh numbers 200#, 400#, and 800# respectively; then using alcohol to preliminarily clean the tool surface to remove water-soluble impurities and dirt; and then using acetone to deeply clean the tool surface to remove oil stains on the tool surface.

[0010] On the other hand, the present invention provides a coating for a lawn mowing robot tool, which is prepared by the above method.

[0011] It should be noted that the chromium carbide in the brazing filler metal plays a wear-resistant role in the coating, increases the wear resistance of the coating, and can extend the service life of the tool. NiCrBSi not only provides matrix support for chromium carbide and improves the bonding strength of the coating, but also provides low-melting-point elements to create conditions for subsequent induction heating.

[0012] Beneficial effects:

[0013] 1. The present invention forms a NiCrBSi-CrC coating on the surface of the mowing robot tool, which can significantly enhance the wear resistance of the tool, especially when facing hard grass stems and foreign objects.

[0014] 2. The present invention uses NiCrBSi-CrC powder as solder, thereby avoiding the use of pure single elements and having good economy.

[0015] 3. The present invention first applies the slurry to the surface of the tool and allows it to dry to enhance the bonding between the coating and the tool surface and improve the strength of the coating. Then, it is preheated by baking, which can further improve the bonding strength between the coating and the tool and discharge gas and part of the carbon through baking. Finally, the coating is brazed by induction heating to fill the holes with low-melting-point elements in the coating, thereby improving the compactness of the coating and making the tool have a higher bonding strength.

[0016] 4. NiCrBSi-CrC coating has good corrosion resistance and can effectively resist the erosion of various chemical substances (such as grass juice, moisture, etc.) that may be exposed during operation, protect the tool substrate and extend the service life of the tool.

[0017] 5. NiCrBSi-CrC coating can further improve the impact resistance of the tool in harsh working environments, reduce the damage or cracking of the tool during use, and greatly improve the cutting effect.

[0018] 6. The preparation method has low cost and is easy to operate without complicated equipment. After drying at room temperature, heating treatment is performed, which can effectively enhance the bonding force between the coating and the substrate, thereby improving the wear resistance and service life of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Flow chart of the coating preparation of the present invention.

[0020] Figure 2 It is a schematic diagram of the structure of the tool coating of the present invention.

[0021] Figure 3 This is a microstructure diagram of the tool coating in Example 1 of the present invention.

[0022] Figure 4 This is the energy spectrum of the tool coating in Example 1 of the present invention.

[0023] Graphic markings: 1. tool, 2. coating. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] The present invention provides a coating for a lawn mowing robot cutter and a preparation method thereof, wherein please refer to Figure 1 , and its preparation method mainly comprises the following steps: Step 1, prepare solder, the solder is NiCrBSi-CrC powder, which is obtained by mechanically mixing NiCrBSi powder and CrC powder, wherein the mass of NiCrBSi is 55-70% of the total mass of the solder; the mass fraction of each element in the NiCrBSi powder is: Cr 15-18%, B 1-2.5%, Si 1.5-2%, and the balance is Ni; Step 2: slowly add solder to the polyvinyl alcohol aqueous solution and stir evenly to obtain a slurry; wherein the mass of the polyvinyl alcohol is 2% of the mass of the solder; Step 3: Grind the tool surface with 200#, 400#, and 800# sandpaper respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and dirt; then use acetone to deeply clean the tool surface to remove oil stains on the tool surface; Step 4: Apply the slurry to the cutting surface of the tool with a thickness of 0.4 to 0.8 mm, and let it stand and dry at room temperature for 12 to 24 hours to obtain a tool loaded with a coating; Step 5: Preheat the coated tool by baking at 750-850°C for 30 minutes; Step 6: Use induction heating equipment to braze the preheated tool with a coating, and keep the heating temperature at 1000-1150℃. Figure 2 As shown, a coating 2 is applied to a tool 1 .

[0026] It should be noted that the order of step 2 and step 3 can be adjusted. The technical solution of the present invention is described in detail below in conjunction with specific embodiments and comparative examples.

[0027] Example 1

[0028] This embodiment discloses a method for preparing a coating for a lawn mowing robot cutter, which mainly includes the following steps: Step 1, solder preparation: prepare solder, the solder is NiCrBSi-CrC powder, wherein the mass of NiCrBSi is 60% of the total mass of NiCrBSi-CrC powder; the mass fraction of each element in NiCrBSi powder is: Cr 15%, B 1.5%, Si 2%, and the balance is Ni; Step 2: Tool pretreatment: Grind the tool surface with 200#, 400#, and 800# sandpaper respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and slight dirt; then use acetone to deeply clean the tool surface to remove oil and other impurities on the tool surface; Step 3, preparing slurry: slowly adding solder to the polyvinyl alcohol (PVA) aqueous solution, stirring evenly to obtain slurry; avoiding agglomeration, and stirring with a stirrer for 30 minutes to ensure sufficient mixing to obtain slurry; wherein the mass of polyvinyl alcohol is 2% of the mass of the solder; Step 4: Slurry coating: After the surface of the tool pretreated in step 2 is completely dry, the slurry is coated and bonded to the cutting surface of the tool, with a coating thickness of 0.8 mm, and the coated tool is left to dry at room temperature for 24 hours; Step 5: Preheat the coated tool by baking at 750°C for 30 minutes; Step 6: Heating, melting and coating generation: Use induction heating equipment to braze the lawn mowing robot tool with the coating, and control the heating temperature at 1050°C to fully melt the NiCrBSi-CrC coating, thereby promoting a close combination of the coating and the substrate, and forming a high-quality NiCrBSi-CrC coating on the tool surface.

[0029] Figure 3 The microstructure diagram of the tool obtained in this embodiment is shown. It can be seen from the figure that the interface between the coating and the tool is tightly bonded, and there are fewer defects on the coating, indicating that the coating is fully melted during the induction heating process. Figure 4 The energy spectrum of the coating is shown in the figure. It can be seen from the figure that the main elements in the coating are Ni, Cr, and Si. Figure 3 and Figure 4 It can be seen that a high-quality NiCrBSi-CrC coating is formed on the tool surface.

[0030] Example 2

[0031] This embodiment discloses a method for preparing a coating for a lawn mowing robot cutter, which mainly includes the following steps: Step 1, solder preparation: prepare solder, the solder is NiCrBSi-CrC powder, wherein the mass of NiCrBSi is 55% of the total mass of NiCrBSi-CrC powder; the mass fraction of each element in NiCrBSi powder is: Cr 16.5%, B1%, Si 1.5%, and the balance is Ni; Step 2: Tool pretreatment: Grind the tool surface with 200#, 400#, and 800# sandpaper respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and slight dirt; then use acetone to deeply clean the tool surface to remove oil and other impurities on the tool surface; Step 3, preparing slurry: slowly adding solder to the polyvinyl alcohol (PVA) aqueous solution, stirring evenly to obtain slurry; avoiding agglomeration, and stirring with a stirrer for 30 minutes to ensure sufficient mixing to obtain slurry; wherein the mass of polyvinyl alcohol is 2% of the mass of the solder; Step 4: Slurry coating: After the surface of the tool pretreated in step 2 is completely dry, the slurry is coated and bonded to the cutting surface of the tool, with a coating thickness of 0.6 mm, and the coated tool is left to dry at room temperature for 24 hours; Step 5: preheat the tool loaded with the coating by baking at 800°C for 30 minutes; Step 6: Heating, melting and coating generation: Use induction heating equipment to braze the lawn mowing robot tool with the coating, and control the heating temperature at 1150°C to fully melt the NiCrBSi-CrC coating, thereby promoting a close combination of the coating and the substrate, and forming a high-quality NiCrBSi-CrC coating on the tool surface.

[0032] Example 3

[0033] This embodiment discloses a method for preparing a coating for a lawn mowing robot cutter, which mainly includes the following steps: Step 1, solder preparation: prepare solder, the solder is NiCrBSi-CrC powder, wherein the mass of NiCrBSi is 65% of the total mass of NiCrBSi-CrC powder; the mass fraction of each element in NiCrBSi powder is: Cr 18%, B 2.2%, Si 1.7%, and the balance is Ni; Step 2: Tool pretreatment: Grind the tool surface with 200#, 400#, and 800# sandpaper respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and slight dirt; then use acetone to deeply clean the tool surface to remove oil and other impurities on the tool surface; Step 3, preparing slurry: slowly adding solder to the polyvinyl alcohol (PVA) aqueous solution, stirring evenly to obtain slurry; avoiding agglomeration, and stirring with a stirrer for 30 minutes to ensure sufficient mixing to obtain slurry; wherein the mass of polyvinyl alcohol is 2% of the mass of the solder; Step 4: Slurry coating: After the tool surface pretreated in step 2 is completely dry, the slurry is coated and bonded to the tool cutting surface with a coating thickness of 0.5 mm, and the coated tool is left to dry at room temperature for 24 hours; Step 5: Preheat the coated tool by baking at 850°C for 30 minutes; Step 6: Heating, melting and coating generation: Use induction heating equipment to braze the lawn mowing robot tool with the coating, and control the heating temperature at 1100°C to fully melt the NiCrBSi-CrC coating, thereby promoting a close combination of the coating and the substrate, and forming a high-quality NiCrBSi-CrC coating on the tool surface.

[0034] Example 4

[0035] This embodiment discloses a method for preparing a coating for a lawn mowing robot cutter, which mainly includes the following steps: Step 1, solder preparation: prepare solder, the solder is NiCrBSi-CrC powder, wherein the mass of NiCrBSi is 67% of the total mass of NiCrBSi-CrC powder; the mass fraction of each element in NiCrBSi powder is: Cr 17%, B 1.8%, Si 1.7%, and the balance is Ni; Step 2: Tool pretreatment: Grind the tool surface with 200#, 400#, and 800# sandpaper respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and slight dirt; then use acetone to deeply clean the tool surface to remove oil and other impurities on the tool surface; Step 3, preparing slurry: slowly adding solder to the polyvinyl alcohol (PVA) aqueous solution, stirring evenly to obtain slurry; avoiding agglomeration, and stirring with a stirrer for 30 minutes to ensure sufficient mixing to obtain slurry; wherein the mass of polyvinyl alcohol is 2% of the mass of the solder; Step 4: Slurry coating: After the tool surface pretreated in step 2 is completely dry, the slurry is coated and bonded to the tool cutting surface with a coating thickness of 0.4 mm, and the coated tool is left to dry at room temperature for 24 hours; Step 5: preheat the coated tool by baking at 820°C for 30 minutes; Step 6: Heat, melt and generate coating: Use induction heating equipment to braze the lawn mowing robot tool and control the heating temperature at 1120°C to fully melt the NiCrBSi-CrC coating, thereby promoting a close combination of the coating and the substrate, and forming a high-quality NiCrBSi-CrC coating on the tool surface.

[0036] Comparative Example 1

[0037] This comparative example discloses a method for processing a blade of a lawn mowing robot, which mainly includes the following steps: Step 1: Quenching preparation: heating furnace, cooling medium, thermometer, etc.; Step 2: Pretreatment of the tool substrate: Use 200#, 400#, and 800# sandpaper to grind the surface of the tool substrate respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and slight dirt; then use acetone to deeply clean the tool surface to remove impurities such as oil on the tool surface; Step 3: Preheat the tool: Make sure there are no obvious cracks, gaps or rust on the surface of the tool, set the preheating temperature to 600℃ and the preheating time to 30 minutes; Step 4: Heating the tool: Place the tool in the heating furnace, make sure it is firmly in place and does not touch the furnace wall, set the heating temperature to 1050°C, maintain the temperature for 1 hour, and use a thermometer to monitor the heating process in real time to ensure that the temperature is uniform throughout the heating process; Step 5: Cool the tool: Take out the tool, select oil as the cooling medium, and cool it quickly; Step 6: Tempering: After the tool in step 5 cools to room temperature, perform tempering at a temperature of 500°C for 2 hours. Step 7: Grinding and polishing: Make sure the tool in step 6 is completely cooled, and grind and polish the tool with sandpaper of mesh size 600#, 800#, and 1000# to remove the oxide layer or other contaminants that may be formed during the quenching process.

[0038] It should be noted that, in order to improve the performance of the tool in Comparative Example 1, the tool was subjected to quenching and tempering steps.

[0039] The cutting tools prepared in Examples 1-4 and the cutting tools of Comparative Example 1 that had undergone surface treatment were subjected to hardness tests and wear tests. The test results are shown in Table 1 below.

[0040] Among them, hardness test: a Vickers hardness tester is used to evaluate the hardness of the lawn mowing robot knives prepared in Examples 1 to 4 and Comparative Example 1.

[0041] Wear test: The wear resistance of the tools prepared in Examples 1 to 4 and Comparative Example 1 was tested using a friction and wear tester. Experimental parameter settings: The pin-disk reciprocating wear mode was adopted, and the experimental load was set to 50N to simulate the force that the tool bears during cutting; the time was set to 20min to fully evaluate the wear resistance of the tool.

[0042] Table 1 Hardness and wear test results of the tools obtained in Examples 1-4 and Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Hardness (HV) 882 910 901 890 680 <![CDATA[Wear amount (mm 3 )]]> 0.051 0.048 0.053 0.050 0.2

[0043] (1) After testing the knives prepared in Examples 1 to 4, the hardness of the coating prepared by the present invention is about HV900, which is greater than the hardness of the cutting surface of the quenched lawn mowing robot knife, which is about HV680. The cutting ability of the knife is significantly improved.

[0044] (2) Through reciprocating wear of the pin and disk, under the test conditions of 50N and 20min, the wear amount of the lawn mowing robot blade coated with the coating in Examples 1 to 4 is about 0.05mm 3 The wear amount of the quenched lawn mowing robot tool in Example 1 is 0.2 mm. 3 , the coated tool has better wear resistance;

[0045] (3) The high content of Ni and Cr elements in the coating improves the corrosion resistance of the tool and can reduce the corrosion of the tool edge during cutting operations.

[0046] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any equivalent changes or modifications made according to the essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a coating for a lawn mowing robot tool, characterized in that: The main steps are as follows: Step 1, preparing solder, wherein the solder is NiCrBSi-CrC powder, which is obtained by mechanically mixing NiCrBSi powder and CrC powder, wherein the mass of NiCrBSi powder is 55-70% of the total mass of the solder; Step 2: slowly add solder to the polyvinyl alcohol aqueous solution and stir evenly to obtain a slurry; Step 3: Apply the slurry to the cutting surface of the tool with a coating thickness of 0.4-0.8 mm, and let it stand and dry at room temperature for 12-24 hours to obtain a tool loaded with a coating; Step 4: preheat the coated tool at 750-850°C for 30 minutes; Step 5: Use induction heating equipment to braze the coating on the tool treated in step 4, and keep the heating temperature at 1000-1150°C.

2. The method for preparing a coating for a lawn mowing robot tool according to claim 1, characterized in that: In step 1, the mass fractions of the elements in the NiCrBSi powder are: Cr 15-18%, B 1-2.5%, Si 1.5-2%, and the balance is Ni.

3. The method for preparing a coating for a lawn mowing robot tool according to claim 1, characterized in that: In step 2, the mass of polyvinyl alcohol is 2% of the mass of the solder.

4. The method for preparing a coating for a lawn mowing robot tool according to claim 1, characterized in that: In step three, before applying the slurry, the tool is pretreated. The specific method of pretreatment is: grind the tool surface with sandpaper of mesh size 200#, 400#, and 800# respectively; then use alcohol to preliminarily clean the tool surface to remove water-soluble impurities and dirt; then use acetone to deeply clean the tool surface to remove oil stains on the tool surface.

5. A coating for a lawn mowing robot tool, characterized in that: The invention is prepared by the method described in any one of claims 1 to 4.

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