High-strength wear-resistant alloy steel and preparation method thereof

Abstract

The invention discloses high-strength wear-resistant alloy steel and a preparation method thereof, and belongs to the technical field of alloy steel materials. The high-strength wear-resistant alloy steel is obtained by firstly mixing composite carbon fibers and 24CrNiMoY alloy steel powder, then uniformly laying the mixture on the surface of a steel substrate, then firstly carrying out high-temperature pretreatment in a mixed gas atmosphere, and then carrying out laser cladding, wherein the composite carbon fiber is obtained by carrying out mixed spinning and roasting on polyacrylonitrile, titanium carbide and polystyrene microspheres, immersing into a nickel-based mixed solution and then carrying out calcination reduction, and the high-strength wear-resistant alloy steel prepared by the preparation method disclosed by the invention is relatively good in wear resistance, relatively good in impact toughness and relatively high in strength.

Description

Technical Field

[0001] The invention relates to high-strength wear-resistant alloy steel and a preparation method thereof. Background Art

[0002] With the development of industrial technology, the requirements for material properties are increasing, especially in terms of wear resistance and strength. As a widely used engineering material, 24CrNiMoY alloy steel has demonstrated its irreplaceable role in numerous fields, such as heavy machinery, automotive manufacturing, and aerospace. However, traditional 24CrNiMoY alloy steel faces challenges in practical applications, such as insufficient wear resistance and strength, which greatly limits its further application and development.

[0003] To address these issues, the common approach is to add titanium carbide (TiC) to alloy steels. Due to its high hardness and excellent wear resistance, titanium carbide is considered an ideal reinforcing phase. In theory, adding an appropriate amount of titanium carbide to 24CrNiMoY alloy steel can significantly improve the steel's wear resistance and strength. However, in practice, titanium carbide particles have been found to have poor dispersion within the alloy steel matrix and are prone to agglomeration. This uneven distribution not only fails to effectively improve the material's overall performance, but can also lead to localized stress concentrations, causing defects such as cracking, seriously impacting the quality and service life of the alloy steel.

[0004] Therefore, the applicant prepared a high-strength wear-resistant alloy steel to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength wear-resistant alloy steel and a preparation method thereof, so as to solve the technical problems mentioned in the above background technology.

[0006] The technical solution for achieving the purpose of the present invention is: In a first aspect, the present invention provides a high-strength wear-resistant alloy steel, which is obtained by first mixing composite carbon fiber and 24CrNiMoY alloy steel powder and then evenly laying them on the surface of a steel substrate, then pre-treating them at high temperature in a mixed gas atmosphere, and then performing laser cladding.

[0007] Furthermore, the steel substrate is a Q235 steel substrate.

[0008] Furthermore, the composite carbon fiber is obtained by spinning polyacrylonitrile, titanium carbide and polystyrene microspheres, baking them, immersing them in a nickel-based mixed solution and then calcining and reducing them.

[0009] Furthermore, the mixed gas includes acetylene, hydrogen carrying thiophene, and nitrogen.

[0010] In a second aspect, the present invention provides a method for preparing the high-strength wear-resistant alloy steel as described in the first aspect, comprising the following steps: (1) Pre-treatment of the steel substrate by grinding, washing, drying, etc.; (2) Mix 1-1.4 parts by mass of composite carbon fiber with 98.6-99 parts by mass of alloy steel powder, add 75-85 parts by mass of anhydrous ethanol and continue mixing, then put it into a ball mill and mix it at 200-400 r / min for 4.5-5.5 hours, and finally put it into a vacuum drying oven to dry and remove the anhydrous ethanol, completing the preparation of the laser cladding material; (3) A layer of laser cladding material obtained in step (2) is laid on the surface of the steel substrate treated in step (1), and then the temperature is raised to 675~685℃ under a nitrogen atmosphere, and then acetylene and hydrogen containing thiophene solution are introduced, and the reaction is carried out at normal pressure for 55~65 minutes to complete the high-temperature pretreatment step.

[0011] (4) The steel substrate covered with the laser cladding material after the treatment in step (3) is laser clad to form a wear-resistant alloy steel layer with a thickness of 4 to 5 mm on the surface of the steel substrate.

[0012] Furthermore, the preparation method of the composite carbon fiber is as follows: urea, nickel nitrate, ethanol and water are mixed to obtain a nickel-based mixed solution, wherein the molar ratio of urea to nickel nitrate is 3:1, the concentration of nickel nitrate in the nickel-based mixed solution is 0.1 mol / L, and the volume of ethanol accounts for 20% of the total volume of the nickel-based mixed solution; then the composite carbon fiber blank is placed in a nickel-based mixed solution with a mass of 1.42 to 1.44 times that of the composite carbon fiber blank and vacuum impregnated for 12 hours; then the composite carbon fiber blank is placed in a high-pressure reactor and reacted in an oil bath at 115 to 125°C for 3 hours; during this period, the metal nickel ions are uniformly precipitated on the surface of the composite carbon fiber blank in the form of hydroxide and then taken out to dry; then the composite carbon fiber blank is calcined at 400°C under nitrogen protection for 3 hours to calcine the nickel hydroxide into nickel oxide; then the temperature is raised to 450°C and 5L / min hydrogen is introduced for reaction for 1 hour to reduce the nickel oxide into metal nickel nanoparticles to obtain a composite carbon fiber.

[0013] Furthermore, the preparation method of the composite carbon fiber blank is as follows: 1 part by mass of polyacrylonitrile is added to 9 parts by mass of N,N-dimethylformamide solution, stirred at a constant temperature of 75-85°C for 115-125 minutes, then 0.45-0.55 parts by mass of titanium carbide powder and 1.5-2.5 parts by mass of polystyrene microspheres are added, and stirring is continued for 3.5-4.5 hours, and then electrospinning is performed to obtain titanium carbide composite fibers; the titanium carbide composite fibers are placed in a 40°C oven and dried overnight, heated to 195-205°C in an inert gas atmosphere, kept warm for 115-125 minutes, and then heated to 550-650°C and kept warm for 115-125 minutes to obtain a composite carbon fiber blank with a porous structure.

[0014] Furthermore, the volume ratio of thiophene to ethanol in the thiophene solution is 0.15-0.17:99.83-99.85.

[0015] Furthermore, the gas flow rate of acetylene is 1 L / min, the gas flow rate of hydrogen carrying thiophene solution is 2 L / min, and the gas flow rate of nitrogen is 5 L / min.

[0016] Furthermore, the process parameters of the laser cladding are as follows: laser power is 1200~2000W, scanning speed is 6~8mm / s, and surface energy density is 50~62.5J / mm 2 .

[0017] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The present invention provides a high-strength wear-resistant alloy steel, which is obtained by first mixing composite carbon fibers and alloy steel powder and then evenly laying them on the surface of a steel substrate, then pre-treating them at high temperature in a mixed gas atmosphere, and then performing laser cladding. The obtained high-strength wear-resistant alloy steel has good strength and high wear resistance.

[0018] (2) The present invention prepares a wear-resistant alloy steel layer by using composite carbon fibers obtained by spinning and calcining polyacrylonitrile, titanium carbide, and polystyrene microspheres, and then immersing them in a nickel-based mixed solution and then calcining and reducing them as a raw material, wherein titanium carbide has good hardness and wear resistance, and can effectively enhance the wear resistance and strength of the wear-resistant alloy steel layer. The present invention prepares a wear-resistant alloy steel layer by spinning and calcining titanium carbide, polyacrylonitrile, and polystyrene microspheres, and then immersing them in a nickel-based mixed solution and then calcining and reducing them, and then adding the composite carbon fibers to the wear-resistant alloy steel layer, which can effectively improve the cracking problem caused by the agglomeration of a single titanium carbide.

[0019] (3) The present invention mixes composite carbon fibers with alloy steel powder and evenly lays them on the surface of the steel substrate. During high-temperature pretreatment in a mixed gas atmosphere, the nickel in the composite carbon fibers is transformed from the original spherical shape into a rhombus structure with small planes and corners at high temperature. Acetylene in the mixed gas is used as a carbon source to in situ grow double-helix carbon nanofibers at the two corners of the rhombus nickel catalyst. Subsequently, laser cladding is performed. The α-Fe carbon atom capacity in the wear-resistant alloy steel layer reaches its limit, so that some carbon fibers remain incompletely dissolved. The iron and chromium atoms inside the original austenite grains continuously diffuse to the surface of the carbon fibers to react with them at the interface to generate CrFe7C 0.45Carbide wraps the graphite in situ to form a micron-sized white fibrous structure. During the friction process, the carbide on the surface of the white fibrous structure is partially worn off, exposing the coated graphite, and part of the graphite is worn off into the grinding debris, acting as a solid lubricant, reducing the friction coefficient and improving wear resistance. At the same time, the molten 24CrNiMoY uses capillary action to fill the pores of the porous composite carbon fiber, and the composite carbon fiber and 24CrNiMoY are firmly combined together through a mechanical interlocking structure. A large number of double-helical carbon nanofibers grow on the surface and pores of the composite carbon fiber, that is, a large number of double-helical carbon nanofibers are also combined between the cross-section of the composite carbon fiber and the 24CrNiMoY, which can effectively disperse stress, improve the impact toughness of the wear-resistant alloy steel layer, and thus improve the impact toughness of the high-strength wear-resistant alloy steel. DETAILED DESCRIPTION

[0020] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0021] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0022] The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] Some of the raw materials of the embodiments of the present invention and the comparative examples are as follows: The chemical composition of Q235 steel substrate is: C: 0.14~0.22%, Mn: 0.3~0.65%, Si: ≤0.3%, S≤0.05%, P≤0.045%, the balance is iron; the density is 7.85g / cm 3 ; Hardness is 165HV; Tensile strength is 375460MPa, melting point is 1493, elastic modulus is 210GPa: Size: 100mm*100mm*10mm.

[0024] The chemical composition of 24CrNiMoY alloy steel powder is: C: 0.243%, Cr: 0.887%, Ni: 0.937%, Mo: 0.503%, Mn: 0.989%, Si: 0.382%, Y: 1.3%, Fe: 94.76%; D 50 It is 104μm.

[0025] Carbon fiber powder: density 1.77g / cm 3 , elongation: 1.52%, carbon content 95.4%, diameter 6μm, length 42μm, modulus 238GPa, strength 4950MPa.

[0026] (Example 1) A method for preparing high-strength wear-resistant alloy steel comprises the following steps: (1) First, use an angle grinder to grind the steel substrate to remove the rust on the surface of the steel substrate, and grind the steel substrate to a smooth and bright finish. Then, use alcohol to clean it to remove the debris generated during the grinding process and the oil stains that originally remained on the surface of the steel substrate. Finally, use a hair dryer to dry it to complete the pretreatment of the steel substrate. (2) Mix 1 part by mass of composite carbon fiber with 99 parts by mass of alloy steel powder, add zirconia ceramic grinding balls at a ball-to-material ratio of 1:3, add 75 parts by mass of anhydrous ethanol and continue mixing, then put it into a ball mill and mix it at 200 r / min for 4.5 hours, and finally put it into a vacuum drying oven to dry and remove the anhydrous ethanol, completing the preparation of the laser cladding material; (3) A layer of laser cladding material obtained in step (2) is laid on the surface of the steel substrate treated in step (1), and then the temperature is raised to 675°C at 10°C / min in a nitrogen atmosphere, and then acetylene and hydrogen containing thiophene solution are introduced, and the reaction is carried out at normal pressure for 55 minutes to complete the high-temperature pretreatment step.

[0027] (4) The steel substrate covered with the laser cladding material after the treatment in step (3) is laser clad to form a 5 mm thick wear-resistant alloy steel layer on the surface of the steel substrate.

[0028] The preparation method of the composite carbon fiber is as follows: urea, nickel nitrate, ethanol and water are mixed to obtain a nickel-based mixed solution, wherein the molar ratio of urea to nickel nitrate is 3:1, the concentration of nickel nitrate in the nickel-based mixed solution is 0.1 mol / L, and the volume of ethanol accounts for 20% of the total volume of the nickel-based mixed solution; then, the composite carbon fiber blank is placed in the nickel-based mixed solution with a mass 1.42 times that of the composite carbon fiber blank and vacuum impregnated for 12 hours; then, the composite carbon fiber blank is placed in a high-pressure reactor and reacted in an oil bath at 115° C. for 3 hours; during this period, metal nickel ions are uniformly precipitated on the surface of the composite carbon fiber blank in the form of hydroxide, and then taken out and dried; then, the composite carbon fiber blank is calcined at 400° C. for 3 hours under nitrogen protection to calcine the nickel hydroxide into nickel oxide; then, the temperature is raised to 450° C., 5 L / min hydrogen is introduced to react for 1 hour, and the nickel oxide is reduced to metal nickel nanoparticles; the composite carbon fiber is ground and sieved to obtain a composite carbon fiber with a length of 42 μm.

[0029] The preparation method of the composite carbon fiber blank is as follows: 1 part by mass of polyacrylonitrile is added to 9 parts by mass of N,N-dimethylformamide solution, stirred at a constant temperature of 75°C for 115 minutes, then 0.45 parts by mass of titanium carbide powder with a size of 2 μm and 1.5 parts by mass of polystyrene microspheres with a particle size of 80 nm are added, and stirring is continued for 3.5 hours, followed by electrospinning to obtain titanium carbide composite fibers; the titanium carbide composite fibers are placed in a 40°C oven for drying overnight, heated to 195°C in an inert gas atmosphere, kept warm for 115 minutes, and then heated to 550°C at a rate of 3°C / min and kept warm for 115 minutes to obtain a composite carbon fiber blank with a porous structure having a diameter of 6 μm.

[0030] The volume ratio of thiophene to ethanol in the thiophene solution is 0.15:99.85.

[0031] The gas flow rate of the acetylene is 1 L / min, the gas flow rate of the hydrogen gas carrying the thiophene solution is 2 L / min, and the gas flow rate of the nitrogen gas is 5 L / min.

[0032] The process parameters of the laser cladding are as follows: laser power 2000W, scanning speed 8mm / s, and surface energy density 62.5J / mm 2 .

[0033] (Example 2) A method for preparing high-strength wear-resistant alloy steel comprises the following steps: (1) First, use an angle grinder to grind the steel substrate to remove the rust on the surface of the steel substrate, and grind the steel substrate to a smooth and bright finish. Then, use alcohol to clean it to remove the debris generated during the grinding process and the oil stains that originally remained on the surface of the steel substrate. Finally, use a hair dryer to dry it to complete the pretreatment of the steel substrate. (2) 1.2 parts by mass of composite carbon fiber was mixed with 98.8 parts by mass of alloy steel powder. Zirconia ceramic grinding balls were added at a ball-to-material ratio of 1:3, and 80 parts by mass of anhydrous ethanol was added to continue mixing. The mixture was then placed in a ball mill at 300 r / min and mixed for 5 h. The mixture was finally placed in a vacuum drying oven to dry and remove the anhydrous ethanol, thereby completing the preparation of the laser cladding material. (3) A layer of laser cladding material obtained in step (2) is laid on the surface of the steel substrate treated in step (1), and then the temperature is raised to 680°C at 10°C / min in a nitrogen atmosphere, and then acetylene and hydrogen containing thiophene solution are introduced, and the reaction is carried out at normal pressure for 60 minutes to complete the high-temperature pretreatment step.

[0034] (4) The steel substrate covered with the laser cladding material after the treatment in step (3) is laser clad to form a 5 mm thick wear-resistant alloy steel layer on the surface of the steel substrate.

[0035] The preparation method of the composite carbon fiber is as follows: urea, nickel nitrate, ethanol and water are mixed to obtain a nickel-based mixed solution, wherein the molar ratio of urea to nickel nitrate is 3:1, the concentration of nickel nitrate in the nickel-based mixed solution is 0.1 mol / L, and the volume of ethanol accounts for 20% of the total volume of the nickel-based mixed solution; then, the composite carbon fiber blank is placed in the nickel-based mixed solution with a mass 1.43 times that of the composite carbon fiber blank and vacuum impregnated for 12 hours; then, the composite carbon fiber blank is placed in a high-pressure reactor and reacted in an oil bath at 120° C. for 3 hours; during this period, metal nickel ions are uniformly precipitated on the surface of the composite carbon fiber blank in the form of hydroxide, and then taken out and dried; then, the composite carbon fiber blank is calcined at 400° C. for 3 hours under nitrogen protection to calcine the nickel hydroxide into nickel oxide; then, the temperature is raised to 450° C., 5 L / min hydrogen is introduced to react for 1 hour, and the nickel oxide is reduced to metal nickel nanoparticles; the composite carbon fiber is ground and sieved to obtain a composite carbon fiber with a length of 42 μm.

[0036] The preparation method of the composite carbon fiber blank is as follows: 1 part by mass of polyacrylonitrile is added to 9 parts by mass of N,N-dimethylformamide solution, stirred at a constant temperature of 80°C for 120 minutes, then 0.5 parts by mass of titanium carbide powder with a size of 2 μm and 2 parts by mass of polystyrene microspheres with a particle size of 80 nm are added, and stirring is continued for 4 hours, followed by electrospinning to obtain titanium carbide composite fibers; the titanium carbide composite fibers are placed in a 40°C oven for drying overnight, heated to 200°C in an inert gas atmosphere, kept warm for 120 minutes, and then heated to 600°C at a rate of 3°C / min and kept warm for 120 minutes to obtain a composite carbon fiber blank with a porous structure having a diameter of 6 μm.

[0037] The volume ratio of thiophene to ethanol in the thiophene solution is 0.16:99.84.

[0038] The gas flow rate of the acetylene is 1 L / min, the gas flow rate of the hydrogen gas carrying the thiophene solution is 2 L / min, and the gas flow rate of the nitrogen gas is 5 L / min.

[0039] The process parameters of the laser cladding are as follows: laser power is 1200W, scanning speed is 6mm / s, and surface energy density is 50J / mm 2 .

[0040] (Example 3) A method for preparing high-strength wear-resistant alloy steel comprises the following steps: (1) First, use an angle grinder to grind the steel substrate to remove the rust on the surface of the steel substrate, and grind the steel substrate to a smooth and bright finish. Then, use alcohol to clean it to remove the debris generated during the grinding process and the oil stains that originally remained on the surface of the steel substrate. Finally, use a hair dryer to dry it to complete the pretreatment of the steel substrate. (2) 1.4 parts by mass of composite carbon fiber was mixed with 98.6 parts by mass of alloy steel powder. Zirconia ceramic grinding balls were added at a ball-to-material ratio of 1:3, and 85 parts by mass of anhydrous ethanol was added to continue mixing. The mixture was then placed in a ball mill at 400 r / min and mixed for 5.5 h. The mixture was finally placed in a vacuum drying oven to dry and remove the anhydrous ethanol, thereby completing the preparation of the laser cladding material. (3) A layer of laser cladding material obtained in step (2) is laid on the surface of the steel substrate treated in step (1), and then the temperature is raised to 685°C at 10°C / min in a nitrogen atmosphere, and then acetylene and hydrogen containing thiophene solution are introduced, and the reaction is carried out at normal pressure for 65 minutes to complete the high-temperature pretreatment step.

[0041] (4) The steel substrate covered with the laser cladding material after the treatment in step (3) is laser clad to form a 5 mm thick wear-resistant alloy steel layer on the surface of the steel substrate.

[0042] The preparation method of the composite carbon fiber is as follows: urea, nickel nitrate, ethanol and water are mixed to obtain a nickel-based mixed solution, wherein the molar ratio of urea to nickel nitrate is 3:1, the concentration of nickel nitrate in the nickel-based mixed solution is 0.1 mol / L, and the volume of ethanol accounts for 20% of the total volume of the nickel-based mixed solution; then, a composite carbon fiber blank is placed in the nickel-based mixed solution with a mass 1.44 times that of the composite carbon fiber blank and vacuum impregnated for 12 hours; then, the composite carbon fiber blank is placed in a high-pressure reactor and reacted in an oil bath at 125° C. for 3 hours; during this period, metal nickel ions are uniformly precipitated on the surface of the composite carbon fiber blank in the form of hydroxide, and then the composite carbon fiber blank is taken out and dried; then, the composite carbon fiber blank is calcined at 400° C. for 3 hours under nitrogen protection to calcine the nickel hydroxide into nickel oxide; then, the temperature is raised to 450° C., 5 L / min hydrogen is introduced and reacted for 1 hour to reduce the nickel oxide into metal nickel nanoparticles; the composite carbon fiber is ground and sieved to obtain a composite carbon fiber with a length of 42 μm.

[0043] The preparation method of the composite carbon fiber blank is as follows: 1 part by mass of polyacrylonitrile is added to 9 parts by mass of N,N-dimethylformamide solution, and stirred at a constant temperature of 85°C for 125 minutes, followed by adding 0.55 parts by mass of titanium carbide powder with a size of 2 μm and 2.5 parts by mass of polystyrene microspheres with a particle size of 80 nm, and continuing to stir for 4.5 hours before electrospinning to obtain titanium carbide composite fibers; the titanium carbide composite fibers are placed in a 40°C oven for drying overnight, heated to 205°C in an inert gas atmosphere, kept warm for 125 minutes, and then heated to 650°C at a rate of 3°C / min and kept warm for 125 minutes to obtain a composite carbon fiber blank with a porous structure having a diameter of 6 μm.

[0044] The volume ratio of thiophene to ethanol in the thiophene solution is 0.17:99.83.

[0045] The gas flow rate of the acetylene is 1 L / min, the gas flow rate of the hydrogen gas carrying the thiophene solution is 2 L / min, and the gas flow rate of the nitrogen gas is 5 L / min.

[0046] The process parameters of the laser cladding are as follows: laser power is 1200W, scanning speed is 6mm / s, and surface energy density is 50J / mm 2 .

[0047] (Comparative Example 1) The difference between Comparative Example 1 and Example 2 is that the laser cladding material in Comparative Example 1 is obtained by mixing carbon fiber, titanium carbide and alloy steel powder; the remaining steps and ingredients are the same as those in Example 2.

[0048] (Comparative Example 2) The difference between Comparative Example 2 and Example 2 is that the composite carbon fiber in Comparative Example 2 is obtained by mixed spinning and calcining of polyacrylonitrile, titanium carbide, and polystyrene microspheres; the remaining steps and ingredients are the same as those in Example 2.

[0049] (Comparative Example 3) The difference between Comparative Example 3 and Example 2 is that the high-strength wear-resistant alloy steel in Comparative Example 3 is obtained by first mixing composite carbon fiber and alloy steel powder, then evenly laying them on the surface of the steel substrate, and then performing laser cladding; the remaining steps are the same as Example 2.

[0050] (Effect example) Wear resistance test: The laser clad surface layer of the high-strength wear-resistant alloy steel prepared in the examples and comparative examples, parallel to the bonding surface between the substrate and the laser cladding layer, was sandpapered and mechanically polished. After treatment, the weight was weighed and recorded as M0. It was then placed on an MFT-5000 friction and wear tester using an alumina friction pair, with a load of 25N, an amplitude of 3mm, a test time of 1h, and a speed of 200r / min. The test was performed at room temperature. After the test, it was weighed and the weighed weight was recorded as M1. The loss was calculated as (M0-M1). The test was repeated three times, and the average value was taken as the wear amount of the sample, and the friction coefficient was calculated.

[0051] Tensile performance test: The tensile performance was tested using an AG-X100KN electronic universal material testing machine. At least three specimens were cut from top to bottom along the laser cladding layer of the high-strength wear-resistant alloy steel prepared in the examples and comparative examples, parallel to the interface between the substrate and the laser cladding layer. The surfaces and sides of the tensile specimens were polished to a bright finish using sandpaper of different sizes, ranging from 240# to 800#. The tensile test was conducted at a tensile rate of 0.5 mm / min and at room temperature.

[0052] Impact toughness: The high-strength wear-resistant alloy steels prepared in the examples and comparative examples were tested according to GB / T229-2007 “Charpy pendulum impact test method for metallic materials”.

[0053] Table 1 below shows the performance test results of the high-strength wear-resistant alloy steels of the examples and comparative examples: Table 1

[0054] As can be seen from Table 1 above, the high-strength wear-resistant alloy steels prepared in Examples 1 to 3 have good wear resistance, good impact toughness, and high tensile strength.

[0055] The difference between Comparative Example 1 and Example 2 is that the laser cladding material of Comparative Example 1 directly mixes carbon fiber, titanium carbide and alloy steel powder, rather than pre-compounding carbon fiber and titanium carbide. The weight proportions of carbon fiber and titanium carbide added are the same as those in Example 2. However, due to the poor dispersibility of titanium carbide, a small amount of agglomeration occurs in the laser cladding layer, and carbon nanofibers with a double helix structure cannot be formed during the preparation process. The poor bonding force between the carbon fiber and the metal matrix directly leads to the wear resistance, impact toughness and tensile strength of the high-strength wear-resistant alloy steel being lower than those of the example.

[0056] The difference between Comparative Example 2 and Example 2 is that the composite carbon fibers in Comparative Example 2 are not loaded with nickel metal, and the interface bonding strength between the composite carbon fibers and the matrix is ​​poor. In addition, the carbon nanofibers with a double helix structure are not formed during the preparation process, resulting in the wear resistance, impact toughness, and tensile strength of the high-strength wear-resistant alloy steel being affected and not as good as the various performances of the examples.

[0057] The difference between Comparative Example 3 and Example 2 is that the high-strength wear-resistant alloy steel in Comparative Example 3 was not pretreated at high temperature in a mixed gas atmosphere before laser cladding. Due to the presence of metallic nickel, the interface bonding force between the composite carbon fiber and the matrix is ​​good, but no double helix structured carbon nanofibers are formed during the preparation process. The wear resistance, impact toughness and tensile strength of the high-strength wear-resistant alloy steel in the example are better than those in the example.

[0058] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-strength wear-resistant alloy steel, characterized in that: The high-strength wear-resistant alloy steel is obtained by first mixing composite carbon fibers and alloy steel powder and then evenly laying them on the surface of a steel substrate, then pre-treating them at high temperature in a mixed gas atmosphere, and then performing laser cladding.

2. The high-strength wear-resistant alloy steel according to claim 1, characterized in that: The steel substrate is a Q235 steel substrate.

3. The high-strength wear-resistant alloy steel according to claim 1, characterized in that: The composite carbon fiber is obtained by mixing and spinning polyacrylonitrile, titanium carbide and polystyrene microspheres, calcining the mixed fibers, and then immersing the mixed fibers in a nickel-based solution and calcining and reducing the mixed fibers.

4. The high-strength wear-resistant alloy steel according to claim 1, characterized in that: The mixed gas includes acetylene, hydrogen carrying thiophene, and nitrogen.

5. A method for preparing the high-strength wear-resistant alloy steel according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Pre-treatment of the steel substrate by grinding, washing, drying, etc.; (2) Mix 1-1.4 parts by mass of composite carbon fiber with 98.6-99 parts by mass of alloy steel powder, add 75-85 parts by mass of anhydrous ethanol and continue mixing, then put it into a ball mill and mix it at 200-400 r / min for 4.5-5.5 hours, and finally put it into a vacuum drying oven to dry and remove the anhydrous ethanol, completing the preparation of the laser cladding material; (3) a layer of laser cladding material obtained in step (2) is laid on the surface of the steel substrate treated in step (1), and then the temperature is raised to 675-685°C in a nitrogen atmosphere, and then acetylene and hydrogen containing thiophene solution are introduced, and the reaction is carried out at normal pressure for 55-65 minutes to complete the high-temperature pretreatment step; (4) The steel substrate covered with the laser cladding material after the treatment in step (3) is laser clad to form a wear-resistant alloy steel layer with a thickness of 4 to 5 mm on the surface of the steel substrate.

6. The method for preparing high-strength wear-resistant alloy steel according to claim 5, characterized in that: The preparation method of the composite carbon fiber is as follows: urea, nickel nitrate, ethanol and water are mixed to obtain a nickel-based mixed solution, wherein the molar ratio of urea to nickel nitrate is 3:1, the concentration of nickel nitrate in the nickel-based mixed solution is 0.1 mol / L, and the volume of ethanol accounts for 20% of the total volume of the nickel-based mixed solution; then, the composite carbon fiber blank is placed in the nickel-based mixed solution with a volume of 1.42 to 1.44 times its mass and vacuum impregnated for 12 hours; then, the blank is placed in a high-pressure reactor and reacted in an oil bath at 115 to 125° C. for 3 hours; then, the blank is taken out and dried, calcined at 400° C. under nitrogen protection for 3 hours, and then the temperature is raised to 450° C. and 5 L / min of hydrogen is introduced for reaction for 1 hour to obtain the composite carbon fiber.

7. The method for preparing high-strength wear-resistant alloy steel according to claim 6, characterized in that: The preparation method of the composite carbon fiber blank is as follows: 1 part by mass of polyacrylonitrile is added to 9 parts by mass of N,N-dimethylformamide solution, and the mixture is stirred at a constant temperature of 75-85°C for 115-125 minutes, followed by adding 0.45-0.55 parts by mass of titanium carbide powder and 1.5-2.5 parts by mass of polystyrene microspheres, and the mixture is stirred for 3.5-4.5 hours, followed by electrospinning to obtain titanium carbide composite fibers; the titanium carbide composite fibers are placed in a 40°C oven and dried overnight, and then heated to 195-205°C in an inert gas atmosphere, kept warm for 115-125 minutes, and then heated to 550-650°C and kept warm for 115-125 minutes to obtain the composite carbon fiber blank.

8. The method for preparing high-strength wear-resistant alloy steel according to claim 5, characterized in that: The volume ratio of thiophene to ethanol in the thiophene solution is 0.15-0.17:99.83-99.

85.

9. The method for preparing high-strength wear-resistant alloy steel according to claim 5, characterized in that: The gas flow rate of the acetylene is 1 L / min, the gas flow rate of the hydrogen gas carrying the thiophene solution is 2 L / min, and the gas flow rate of the nitrogen gas is 5 L / min.

10. The method for preparing high-strength wear-resistant alloy steel according to claim 5, characterized in that: The process parameters of the laser cladding are as follows: laser power is 1200~2000W, scanning speed is 6~8mm / s, and surface energy density is 50~62.5J / mm 2 .

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