High-wear-resistance iron-based hypersonic flame spraying coating and preparation method thereof

Abstract

The invention relates to a high-wear-resistance iron-based hypersonic flame spraying coating and a preparation method thereof. The coating is mainly composed of a WC-Co-Cr material, and the powder material comprises the following components in percentage by mass: 4.0-6.0% of C, 2.0-5.0% of Co, 1.0-2.0% of Cr and the balance of Fe. Cr: 3.0 to 5.0%; 9.0 to 11.0 percent of Co; o: < = 0.5%; fe < = 1%; w: the balance. According to the preparation method, the rotary blade which is high in hardness, low in porosity, high in interface bonding strength, excellent in wear resistance and long in service life is obtained by controlling high velocity oxy-fuel parameters and matching with matrix components and a pretreatment process. The coating is reasonable in structural design, the preparation process is simple and controllable, and the obtained product is excellent in performance and suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of wear-resistant coatings, in particular to a high-wear-resistant iron-based supersonic flame spraying coating and a preparation method thereof. Background Art

[0002] As an indispensable key component of agricultural machinery, soil-contacting parts undertake important functions such as tilling and loosening the soil. Their wear resistance directly affects agricultural production efficiency and operation quality. The soil-contacting parts are frequently subjected to impact, friction, chiseling and other effects of soil, gravel and stones, resulting in wear and failure. At present, the wear resistance of soil-contacting parts can be improved by the following methods: first, optimize the tool material and select high-hardness, high-strength alloy steel or tool steel as the tool material to enhance the overall hardness and wear resistance of the tool; second, improve the tool design by optimizing the tool structure and reducing stress concentration on the tool surface to improve the wear resistance and durability of the tool during use. In addition, the use of surface engineering technology to process wear-resistant coatings on steel substrates is also an important means. In recent years, researchers have paid extensive attention to the application of surface engineering technology in the surface wear resistance of agricultural machinery soil-contacting parts.

[0003] The Chinese invention patent application "A cladding powder material and its application as a surface strengthening coating for agricultural machinery soil-contacting parts (CN202311310111.8)" provides a cladding powder material and its application as a surface strengthening coating for agricultural machinery soil-contacting parts. The raw materials of the cladding powder material of the invention are composed of the following components in mass percentage: 48.5wt% Mo powder, 28.2wt% FeB powder, 3wt% Ni powder, 2.5wt% Cr powder, 0.5wt% C powder, and the remainder is Fe powder. The cladding powder material is subjected to surface strengthening treatment by a plasma cladding process. The cladding layer has high density and good wear resistance, and the mechanical properties are effectively improved.

[0004] The Chinese invention patent application "A Highly Wear-Resistant Cultivation Machinery Soil-Contacting Cutter and Its Preparation Method (CN202211434922.4)" discloses an agricultural machinery soil-contacting tool with a highly wear-resistant working layer and its additive manufacturing method. The agricultural machinery soil-contacting tool designed and prepared by the invention has a blade made of a high-hardness and high-wear-resistant diamond composite material, which not only achieves near-net forming of the component and greatly saves costs, but also avoids the wear, peeling and passivation of the coating that is prone to occur during the soil-entering operation, and improves the self-sharpening and service life of the soil-contacting component.

[0005] The Chinese invention patent application "A high-hardness laser cladding coating on the surface of 65Mn steel for rotary tiller and its preparation method (CN202010193467.8)" discloses a high-strength and wear-resistant rotary tiller for a rotary tiller and its preparation method. The invented cladding layer is obtained by mixing nickel-based self-fluxing alloy powder, silicon nitride powder and fluorine-containing additives; by mass percentage, the nickel-based self-fluxing alloy powder accounts for 90-95% of the cladding layer, the silicon nitride powder accounts for 2.25-2.375%, and the remainder is fluorine-containing additives. The comprehensive mechanical properties of the alloy blade are improved, and it has excellent wear resistance and corrosion resistance.

[0006] The Chinese invention patent application "A rotary tiller with a wear-resistant alloy layer welded on the positive blade (CN202122501672.9)" proposes a rotary tiller with a wear-resistant alloy layer welded on the positive blade. A wear-resistant alloy layer is provided on the top and front of the positive blade at the cutting end of the blade body, and the wear-resistant alloy layer is connected to the top of the positive blade by welding. The thickness of the wear-resistant alloy layer is greater than the thickness of the positive blade. The wear-resistant alloy is provided on the top and front of the positive blade, which fully protects the positive blade. The wear-resistant alloy layer increases the durability and wear resistance of the rotary tiller.

[0007] These wear-resistant materials and processes have achieved good results. However, methods such as laser cladding and surfacing welding may cause brittle fracture of the soil-contacting parts. After the wear-resistant coating is processed, heat treatment is required, making the process more complicated. Summary of the invention

[0008] The present invention provides a highly wear-resistant iron-based supersonic flame spraying coating and a preparation method thereof. The present invention directly prepares the coating on the substrate surface of the finished soil-contacting component, and the coating has the advantages of high hardness, high wear resistance, high bonding strength, etc. The preparation method of the wear-resistant coating is simple. The hardness and wear resistance of the soil-contacting component can be effectively improved, the service life of the soil-contacting component can be extended, and the purpose of wear resistance and life extension can be achieved.

[0009] In order to achieve the expected goal, the technical solution proposed by the present invention is specifically as follows:

[0010] A highly wear-resistant iron-based supersonic flame spraying coating, wherein the raw material used for the coating is a powder material, and the powder material comprises the following components by mass percentage:

[0011] C: 4.0-6.0%; Cr: 3.0-5.0%; Co: 9.0-11.0%; O: ≤0.5%; Fe: ≤1%; W: balance; the particle size distribution of the powder material is 15-45 μm; and the coating is prepared by a supersonic flame spraying process.

[0012] The invention discloses a highly wear-resistant iron-based supersonic flame spraying coating, wherein the bulk density of the raw material powder is 4.0-6.0 g / cm3 , preferably 4.75 to 4.85 g / cm 3 , the Hall flow rate is 10.0-15.0 s / 50 g, preferably 13.0-13.5 s / 50 g.

[0013] As a further preferred embodiment, the mass percentages of the components of the powder material are as follows: C: 4.5-5.5%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; and W: balance.

[0014] The invention mixes three raw material powders of WC powder, Co powder and Cr3C2 powder according to the ratio requirements to form WC10Co4Cr mixed powder, selects deionized water as solvent, adds appropriate amount of deionized water to the mixed powder, puts in grinding balls, wet-mills for 8-12 hours in a ball mill, then adds binder and dispersant to prepare slurry, and then puts in the ball mill for wet mixing for a period of time to obtain uniform and stable slurry, and then sprays and granulates the prepared slurry in a centrifugal spray drying tower, and the granulated powder is quickly sintered in a vertical high-temperature sintering furnace after screening and degreasing, and the powder passes through the heating zone and the cooling zone continuously and evenly in a free-falling motion mode, and completes sintering in the heating zone, and the sintering time is 0.1-5s. The protective atmosphere is nitrogen, and finally the sintered powder is graded and classified as required to obtain WC10Co4Cr thermal spray powder with required particle size.

[0015] The purity of the used WC, Co and Cr3C2 powders is ≥99%, the powder particle size is 1-2 μm, and the mass ratio of the WC, Co and Cr3C2 powders is 85.4:10:4.6.

[0016] The present invention provides a method for preparing a highly wear-resistant iron-based supersonic flame spraying coating, comprising the following steps:

[0017] (1) Clean, degrease and remove rust from the surface of the soil-contacting parts;

[0018] (2) sandblasting the surface of the soil-contacting parts after step (1);

[0019] (3) fixing the soil-contacting component substrate treated in step (2) on a stage and performing supersonic flame spraying;

[0020] (4) Coating preparation: The coating is prepared by using a supersonic flame spraying system to obtain a highly wear-resistant iron-based supersonic flame spraying coating.

[0021] Furthermore, in step (1), the oxide layer of the soil contact component substrate is removed by an angle grinder and cleaned with anhydrous ethanol. Oil stains and paint are cleaned with chemical solvents, and if the oil stains have penetrated into the base material, they can be baked with an oxygen-acetylene flame.

[0022] Furthermore, the material of the soil contact component substrate includes 65Mn steel, 60Si2Mn steel, etc.

[0023] Furthermore, in step (2), the surface of the area where the wear-resistant coating is to be processed on the soil-contacting component substrate is subjected to sandblasting roughening treatment to increase the surface roughness (600-680 μm, preferably 620-660 μm), which is conducive to better bonding between the substrate and the coating. The abrasive used for sandblasting must be clean, dry and have sharp edges and corners. After the surface is roughened, it should be kept clean and dry, and sprayed immediately after roughening, and the interval time should not exceed 2 hours.

[0024] Furthermore, in step (3), the soil contact component substrate processed in step (2) is adjusted to a processing position and fixed on a spray processing stage. The spray gun is set to move at a speed of 500-700 mm / s relative to the workpiece, a spray distance of 350-400 mm, and a spray gun step distance of 3-8 mm.

[0025] As a further preference, in the step (3), the spray gun is set to move at a speed of 590-610 mm / s relative to the workpiece, a spraying distance of 365-375 mm, and a spray gun step distance of 4-6 mm.

[0026] Furthermore, in step (4), the spray powder must be dried before use, with a drying temperature of 80-90° C. and a drying time of 1-2 hours. Aviation kerosene is used as fuel, oxygen as a combustion aid, and nitrogen as a powder delivery carrier gas.

[0027] Furthermore, in step (4),

[0028] The fuel used is aviation kerosene, with a flow rate of 28-32L / h (flow rate before gasification) and a pressure of 5-10PSI;

[0029] Oxygen is used as a combustion aid, with a flow rate of 1000-1150L / h and a pressure of 1.6-1.9MPa;

[0030] Nitrogen is used as the powder delivery carrier gas with a flow rate of 20-35L / h and a pressure of 0.54-0.69MPa.

[0031] Furthermore, a highly wear-resistant iron-based supersonic flame sprayed coating is obtained. The surface hardness of the highly wear-resistant supersonic flame sprayed coating for the soil contacting component is greater than 1200 HV 0.5 The wear mass of the sample sprayed with high wear-resistant coating can be reduced by more than 90% compared with the unsprayed coating, and the average bonding strength can be greater than 78MPa. The prepared high wear-resistant coating has good bonding strength, low porosity and excellent wear resistance.

[0032] The high wear-resistant supersonic flame spray coating and preparation method for soil-contacting parts described in the present invention can be directly used on the surfaces of various soil-contacting parts, such as plowshares, rotary tillage blades, deep loosening shovels, etc. The obtained wear-resistant coating has the advantages of high hardness, low porosity, and good bonding strength, and has good comprehensive wear resistance and impact resistance, and the processing and preparation methods are simple and easy to operate. The wear-resistant coating can effectively protect the substrate of the soil-contacting parts to achieve the purpose of wear resistance and life extension. The present invention provides a new process and method for improving the wear resistance of soil-contacting parts and further extending the service life of the parts.

[0033] In the present invention, when the substrate is 65Mn steel, the mass percentage of each component of the powder material is, C: 4.9%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance,

[0034] The wear resistance of the coating was tested using a friction and wear tester and a wet rubber wheel test bench. The grinding ball was a chrome steel ball, the load was 30N, the time was 30min, and the frequency was 120rev / min.

[0035] The wet rubber wheel friction test simulates the soil environment, with a load of 70N, a rubber wheel speed of 100r / min, a sand-water ratio of 3:1, a quartz sand particle size of 50-70 mesh, each sample was worn 4 times, 1000 circles / time, and the total wear distance of each sample was about 2.2km; the wear mass of the sample sprayed with high wear-resistant coating was 0.037~0.044g.

[0036] In the present invention, when the substrate is 60Si2Mn steel, the mass percentage of each component of the powder material is, C: 4.9%; Cr: 4.0%; Co: 10.0%; O≤0.05%.; Fe≤0.5%; W: balance, the wear resistance of the coating is tested by using a friction and wear tester and a wet rubber wheel test bench, the grinding ball is a chrome steel ball, the load is 30N, the time is 30min, and the frequency is 120rev / min;

[0037] The wet rubber wheel friction test simulates the soil environment, with a load of 70N, a rubber wheel speed of 100r / min, a sand-water ratio of 3:1, a quartz sand particle size of 50-70 mesh, each sample was worn 4 times, 1000 circles / time, and the total wear distance of each sample was about 2.2km; the wear mass of the sample sprayed with high wear-resistant coating was 0.033~0.039g.

[0038] Combined with the existing rotary tiller, it was improved and it was found that after the spray coating was set on the rotary tiller model 175, its performance was better than the improved performance of other models.

[0039] This also shows that in order to further enhance the interface bonding strength and wear resistance of the product, appropriate base materials and special spraying materials can be selected.

[0040] Beneficial Effects

[0041] The present invention achieves a hardness of >1200HV through the synergistic effect of spraying material composition, spraying process and substrate composition. 0.5 , high-quality products with bonding strength greater than 74.6MPa and low porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is the microscopic morphology of WC10Co4Cr powder.

[0043] Figure 2 Schematic diagram of coating thickness obtained in Examples 1-2 of the present invention and Comparative Examples 1-2.

[0044] Figure 3 The cross-sectional microscopic morphology of the coatings obtained in Examples 1-2 of the present invention and Comparative Examples 1-2 are shown.

[0045] Figure 4 The microhardness diagram of the coatings prepared in Examples 1-4 of the present invention and Comparative Examples 1-5.

[0046] Figure 5 This is a comparison chart of the friction and wear mass loss of wet rubber wheels in Examples 1 and 2 of the present invention.

[0047] Figure 6 This is a comparison chart of friction and wear mass loss in field tests of Examples 3 and 4 of the present invention.

[0048] Figure 7 The wear scar depth diagram of the experimental group and the control group in Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0050] In the embodiments and comparative examples of the present invention, the powder used for spraying (i.e., raw material powder) is prepared by the following process:

[0051] WC, Co and Cr3C2 powders with a purity of ≥99% are used as raw materials, the powder particle size is 1-2μm, and the mass ratio of WC, Co and Cr3C2 powders is 85.4:10:4.6.

[0052] The three raw material powders of WC powder, Co powder and Cr3C2 powder are mixed into WC10Co4Cr mixed powder according to the ratio requirements. Deionized water is selected as the solvent. An appropriate amount of deionized water is added to the mixed powder, and then grinding balls are put in. After wet grinding in the ball mill for 8 to 12 hours, a binder and a dispersant are added to prepare a slurry, and then it is put into the ball mill for wet mixing for a period of time to obtain a uniform and stable slurry. Then the prepared slurry is sprayed and granulated in a centrifugal spray drying tower. After sieving and degreasing, the granulated powder is quickly sintered in a vertical high-temperature sintering furnace. The powder passes through the heating zone and the cooling zone continuously and evenly in a free-falling motion mode, and the sintering is completed in the heating zone. The sintering time is 0.1 to 5s. The protective atmosphere is nitrogen. Finally, the sintered powder is graded and classified as required to obtain the WC10Co4Cr thermal spray powder with the required particle size.

[0053] Embodiment 1:

[0054] The base material is 65Mn steel, which is the most commonly used 65Mn steel for soil-contacting parts. The basic composition of the base material is shown in Table 1. The spray powder is dried before use at 80°C for 1h. The particle size of the raw powder is 15-45μm, the bulk density is 4.7g / cm, and the Hall flow rate is 13.2s / 50g. The mass percentage of each component of the powder material is C: 4.9%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance. The base material is used with an angle grinder to remove the oxide layer and cleaned with anhydrous ethanol. Oil stains and paint are cleaned with chemical solvents.

[0055] The surface of the 65Mn substrate after degreasing and rust removal is sandblasted to increase the surface roughness (roughness is 630 μm). After the surface is roughened, it is kept clean and dry, and spraying is performed immediately after drying.

[0056] Fix the 65Mn steel substrate on the stage, adjust the processing position and fix it on the spraying stage. Set the spray gun relative to the workpiece to move at a speed of 600mm / s, spray distance: 370mm; spray gun step 5mm, and perform supersonic flame spraying; use aviation kerosene as fuel (flow rate 30L / h, pressure 8PSI), oxygen as a combustion aid (flow rate 1100L / min, pressure 1.70MPa), and nitrogen as a powder carrier gas (flow rate 25L / h, pressure 0.60MPa).

[0057] The microstructure of the surface and cross section of the high wear-resistant supersonic flame sprayed coating is shown in Figure 2 The coating thickness is about 0.25 mm, and the surface microhardness of the coating is 1203 HV 0.5 The bonding strength between the coating and the substrate is 74.6MPa.

[0058] The wear resistance of the coating was tested using a friction and wear tester and a wet rubber wheel test bench (the grinding ball was a chrome steel ball, the load was 30N, the time was 30min, and the frequency was 120rev / min); the results of the reciprocating friction test showed that the friction coefficient increased slowly with the wear time and stabilized at around 0.70; the wet rubber wheel friction test simulated the soil environment (two groups of experiments, load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 laps / time, and the total wear distance of each sample was about 2.2km); the results of the wet rubber wheel friction test are shown in Figure 5 The wear weight of the first group of unsprayed coating samples and sprayed high wear-resistant coating samples were 0.62g and 0.044g respectively, and the wear weight of the second group of unsprayed coating samples and sprayed high wear-resistant coating samples were 0.49g and 0.037g respectively. The wear weight of the samples of the two groups of experiments sprayed with high wear-resistant coatings decreased by 92.9% and 92.5% respectively compared with the unsprayed coatings. The high wear-resistant supersonic flame sprayed coating of the present invention has high hardness, low porosity, good bonding strength and excellent wear resistance.

[0059] Table 165Mn matrix composition content table wt%

[0060]

[0061] Embodiment 2:

[0062] The base material is 60Si2Mn steel, which is the most commonly used steel for soil-contacting parts. The basic composition of the base material is shown in Table 2. The spray powder is dried before use at 80°C for 1 hour. The particle size of the raw powder is 15-45μm and the bulk density is 4.7g / cm 3 , the Hall flow rate is 13.2s / 50g. The mass percentage of each component of the powder material is: C: 4.9%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance.

[0063] Use an angle grinder to remove the oxide layer from the base material and clean it with anhydrous ethanol. Use chemical solvents to clean oil and paint.

[0064] The surface of the 60Si2Mn substrate after degreasing and rust removal is sandblasted to increase the surface roughness (roughness is 630 microns). After the surface is roughened, it is kept clean and dry, and spraying is performed immediately after drying.

[0065] Fix the 60Si2Mn steel substrate on the stage, adjust the processing position and fix it on the spraying stage. Set the spray gun relative to the workpiece to move at a speed of 600mm / s, spray distance: 370mm; spray gun step 5mm, and perform supersonic flame spraying; use aviation kerosene as fuel (flow rate 30L / h, pressure 8PSI), oxygen as a combustion aid (flow rate 1100L / min, pressure 1.7MPa), and nitrogen as a powder carrier gas (flow rate 25L / h, pressure 0.62MPa).

[0066] The microstructure of the surface and cross section of the high wear-resistant supersonic flame sprayed coating is shown in Figure 2 The coating thickness is about 0.25 mm, and the surface microhardness of the coating is 1237 HV 0.5 The bonding strength between the coating and the substrate is 78.4MPa.

[0067] The wear resistance of the coating was tested using a friction and wear tester and a wet rubber wheel test bench (two groups of experiments, load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 circles / time, and the total wear distance of each sample was about 2.2km); the results of the reciprocating friction test showed that the friction coefficient increased slowly with the wear time and stabilized at about 0.70; the results of the wet rubber wheel friction test are shown in Figure 5 The wear weight of the first group of unsprayed coating samples and sprayed high wear-resistant coating samples were 0.79g and 0.039g respectively, and the wear weight of the second group of unsprayed coating samples and sprayed high wear-resistant coating samples were 0.72g and 0.033g respectively. The wear weight of the samples of the two groups of experiments sprayed with high wear-resistant coatings decreased by 95.1% and 95.4% respectively compared with the unsprayed coatings. The high wear-resistant supersonic flame sprayed coating of the present invention has high hardness, low porosity, good bonding strength and excellent wear resistance.

[0068] Table 260Si2Mn matrix composition content table wt%

[0069]

[0070] Verification example:

[0071] Example 3

[0072] The substrate is a soil contact part #175 rotary tiller (i.e. a rotary tiller with a model number of 175). The spray powder is dried before use at a drying temperature of 80°C for 1 hour. The particle size of the raw material powder is 15 to 45 microns, and the mass percentage of each component of the powder material is C: 4.9%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance.

[0073] Use an angle grinder to remove the oxide layer from the rotary tiller and clean it with anhydrous ethanol. Use chemical solvents to clean oil and paint.

[0074] The surfaces on both sides of the rotary tiller blade after degreasing and rust removal are sandblasted to increase the surface roughness (roughness is 650 microns). After the surface is roughened, it is kept clean and dry, and sprayed immediately after drying.

[0075] Fix the rotary tiller on the stage, adjust the processing position and fix it on the spraying stage. Set the spray gun relative to the workpiece to move at a speed of 600mm / s, spray distance: 370mm; spray gun step 5mm, and perform supersonic flame spraying; use aviation kerosene as fuel (flow rate 30L / h, pressure 9PSI), oxygen as a combustion aid (flow rate 1110L / min, pressure 1.8MPa), and nitrogen as a powder carrier gas (flow rate 25L / h, pressure 0.62MPa).

[0076] The surface hardness of the highly wear-resistant supersonic flame sprayed coating is greater than 1189HV 0.5 The spray coating thickness is about 0.25mm and the width is about 15mm. After field tests (the experimental group and the control group were equipped with 10 knives respectively, the operating area was about 70 mu (paddy field / dry land was mixed at an area ratio of 1:1), the rotary tiller speed was 760r / min, the speed was 15Km / h, and the weight comparison was carried out after the test), Figure 6 For the comparison of the average wear mass of the tools, the average wear mass of the control group of #175 rotary tiller blade (uncoated) was 8.88g / blade, and the average wear mass after spraying the coating was 2.93g / blade, and the average wear mass decreased by about 67.0%.

[0077] Example 4

[0078] The base material is a soil contact part #195 rotary tiller. The spray powder is dried before use at 80°C for 1 hour. The particle size of the raw powder is 15-45 microns, and the mass percentage of each component of the powder material is C: 4.9%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance.

[0079] Use an angle grinder to remove the oxide layer from the rotary tiller and clean it with anhydrous ethanol. Use chemical solvents to clean oil and paint.

[0080] The surfaces on both sides of the rotary tiller blade after degreasing and rust removal are sandblasted to increase the surface roughness (roughness is 650 microns). After the surface is roughened, it is kept clean and dry, and sprayed immediately after drying.

[0081] Fix the rotary tiller on the stage, adjust the processing position and fix it on the spray processing stage. Set the spray gun to move at a speed of 600mm / s relative to the workpiece, spray distance: 370mm; spray gun step 5mm, and perform supersonic flame spraying; use aviation kerosene as fuel (flow rate 30L / h, pressure 9PSI), oxygen as a combustion aid (flow rate 1110L / min, pressure 1.8MPa), and nitrogen as a powder carrier gas (flow rate 25L / h, pressure 0.62MPa). The surface hardness of the obtained high wear-resistant supersonic flame sprayed coating is greater than 1243HV 0.5 . The spray coating thickness is about 0.25mm and the width is about 17mm. After field tests (the experimental group and the control group were equipped with 10 knives respectively, the operating area was about 70 mu (paddy field / dry land was mixed at an area ratio of 1:1), the rotary tiller speed was 760r / min, the speed was 15Km / h, and the weight was compared after the test), the average wear mass of the control group of #195 rotary tiller (uncoated) was 12.98g / knife, and the average wear mass after spraying the coating was 6.57g / knife. The average wear mass decreased by about 49.4%.

[0082] Comparative Example 1:

[0083] The other conditions are the same as those in Example 1, except that the powder particle size distribution is changed. Particle size distribution: 40-60 μm. The surface hardness of the obtained high wear-resistant supersonic flame sprayed coating is about 1050 HV 0.5 The wear resistance of the coating was tested using a friction and wear tester (chrome steel ball for the grinding ball, load 30N, time 30min, frequency 120rev / min) and a wet rubber wheel test bench (load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 laps / time, and the total wear distance of each sample was about 2.2km); the friction coefficient was 0.80, and the wet rubber wheel friction test simulated the soil environment. The wear mass of the sample without spraying coating and the sample with high wear-resistant coating was 0.84g and 0.21g respectively, and the wear mass of the sample with high wear-resistant coating decreased by 75.0% compared with the sample without spraying coating. There are many pores in the coating.

[0084] Comparative Example 2:

[0085] The other conditions are the same as those in Example 1, except that the powder formula is changed. The mass percentage of each component of the powder is C: 8.0%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance. The surface hardness of the obtained high wear-resistant supersonic flame sprayed coating is about 1148HV 0.5. The wear resistance of the coating was tested using a friction and wear tester (chrome steel ball for the grinding ball, load 30N, time 30min, frequency 120rev / min) and a wet rubber wheel test bench (load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 circles / time, and the total wear distance of each sample was about 2.2km); the friction coefficient was 0.68, and the wet rubber wheel friction test simulated the soil environment. The wear mass of the sample without spray coating and the sample with high wear-resistant coating was 0.84g and 0.33g respectively. The wear mass of the sample with high wear-resistant coating decreased by 60.7% compared with the sample without spray coating. There are many pores and cracks in the coating. After wear, the coating falls off in layers.

[0086] Comparative Example 3:

[0087] The other conditions are the same as those in Example 3, except that the powder formula is changed. The mass percentage of each component of the powder is C: 5.5%; Cr: 8.0%; Co: 13.0%; O: about 3.0%; Fe: 0%; W: balance. The surface hardness of the obtained high wear-resistant supersonic flame sprayed coating is about 1046HV 0.5 The wear resistance of the coating was tested using a friction and wear tester (chrome steel ball for the grinding ball, load 30N, time 30min, frequency 120rev / min) and a wet rubber wheel test bench (load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 laps / time, and the total wear distance of each sample was about 2.2km); the friction coefficient was 0.62, the wear mass of the sample without spray coating and the sample with high wear-resistant coating was 0.84g and 0.24g respectively, and the wear mass of the sample with high wear-resistant coating decreased by 71.4% compared with the sample without spray coating. There are many pores in the coating, a large number of cracks, and large wear.

[0088] Comparative Example 4:

[0089] The other conditions are the same as those in Example 3, except that the pretreatment of the rotary tiller blade is changed. The surface of the rotary tiller blade is not sandblasted before spraying the coating (roughness < 10 μm). The surface hardness of the obtained high wear-resistant supersonic flame sprayed coating is about 1080 HV 0.5. The wear resistance of the coating was tested using a friction and wear tester (chrome steel ball for the grinding ball, load 30N, time 30min, frequency 120rev / min) and a wet rubber wheel test bench (load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 laps / time, and the total wear distance of each sample was about 2.2km). The friction coefficient is 0.68, and the wear mass of the sample without spray coating and the sample with high wear-resistant coating is 0.84g and 0.39g respectively. The wear mass of the sample with high wear-resistant coating is only 53.5% lower than that of the sample without spray coating. There are many pores and cracks in the coating. After wear, the coating has large-scale flaking.

[0090] Comparative Example 5:

[0091] The other conditions are the same as those in Example 3, except that the spraying distance is changed. The spraying distance is 450 mm. The surface hardness of the obtained high wear-resistant supersonic flame sprayed coating is about 1104 HV. 0.5 . The wear resistance of the coating was tested using a friction and wear tester (chrome steel ball for the grinding ball, load 30N, time 30min, frequency 120rev / min) and a wet rubber wheel test bench (load 70N, rubber wheel speed 100r / min, sand-water ratio 3:1, quartz sand particle size 50-70 mesh, each sample was worn 4 times, 1000 laps / time, and the total wear distance of each sample was about 2.2km). The friction coefficient was 0.71, and the wear mass of the sample without spraying coating and the sample with spraying high wear-resistant coating were 0.84g and 0.14g respectively. The wear mass of the sample with spraying high wear-resistant coating decreased by 83.3% compared with the sample without spraying coating. There are many pores and cracks in the coating. After wear, the coating has small areas of flaking.

Claims

1. A highly wear-resistant iron-based supersonic flame sprayed coating, characterized in that: The raw material used for the coating is a powder material, and the powder material includes the following components by mass percentage: C: 4.0~6.0%; Cr: 3.0~5.0%; Co: 9.0-11.0%; O: ≤0.5%; Fe: ≤1%; W: balance; the particle size distribution of the powder material is 15-45 μm; and the coating is prepared by a supersonic flame spraying process.

2. The highly wear-resistant iron-based supersonic flame sprayed coating according to claim 1, characterized in that: The bulk density of the raw material powder is 4.0~6.0g / cm 3 , preferably 4.75 to 4.85 g / cm 3 , the Hall flow rate is 10.0-15.0 s / 50 g, preferably 13.0-13.5 s / 50 g.

3. The highly wear-resistant iron-based supersonic flame sprayed coating according to claim 1, characterized in that: The mass percentage of each component of the powder material is: C: 4.5-5.5%; Cr: 4.0%; Co: 10.0%; O≤0.05%; Fe≤0.5%; W: balance.

4. A method for preparing a highly wear-resistant iron-based supersonic flame sprayed coating, characterized in that: The following steps are involved: (1) Clean, degrease and remove rust from the surface of the soil-contacting parts; (2) performing a surface sandblasting treatment on the soil contacting component obtained in step (1) until the surface roughness is 600-680 μm; (3) fixing the soil-contacting component substrate treated in step (2) on a stage and performing supersonic flame spraying; Set the spray gun relative to the workpiece moving speed to 500-700mm / s, spray distance: 350-410mm; spray gun step distance 3-8mm; (4) Coating preparation: The coating is prepared by a supersonic flame spraying system to obtain a highly wear-resistant iron-based supersonic flame spraying coating; The material of the soil contact component base includes 65Mn steel, 60Si2Mn steel and the like.

5. The method for preparing a highly wear-resistant iron-based supersonic flame spraying coating according to claim 1, characterized in that: In the step (2), the surface of the area of ​​the soil-contacting component substrate where the wear-resistant coating is to be processed is roughened by sandblasting to increase the surface roughness to 620-660 μm.

6. The method for preparing a highly wear-resistant iron-based supersonic flame spraying coating according to claim 1, characterized in that: In the step (2), after the surface is roughened, it is kept clean and dry, and spraying is performed immediately after roughening, and the interval time cannot exceed 2 hours.

7. The method for preparing a highly wear-resistant iron-based supersonic flame spraying coating according to claim 1, characterized in that: In the step (3), the spray gun is set to move at a speed of 590-610 mm / s relative to the workpiece, a spraying distance of 365-375 mm, and a spray gun step distance of 4-6 mm.

8. The method for preparing a highly wear-resistant iron-based supersonic flame spraying coating according to claim 1, characterized in that: In the step (4), the spray powder is dried before use, the drying temperature is 80-90° C., and the drying time is 1-2 hours.

9. The method for preparing a highly wear-resistant iron-based supersonic flame spraying coating according to claim 1, characterized in that: When the coating is prepared by the supersonic flame spraying system, aviation kerosene is used as fuel, oxygen is used as a combustion aid, and nitrogen is used as a powder carrier gas; wherein: The fuel used is aviation kerosene, with a flow rate of 28-32L / h and a pressure of 5-10PSI; Oxygen is used as a combustion aid, with a flow rate of 1000-1150L / h and a pressure of 1.6-1.9MPa; Nitrogen is used as the powder delivery carrier gas with a flow rate of 20-35L / h and a pressure of 0.54-0.69MPa.

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