A highly wear-resistant tungsten steel alloy and its preparation method

Abstract

The present invention belongs to the technical field of cemented carbide, and specifically relates to a high-wear-resistant tungsten steel alloy and a preparation method thereof. The raw materials of the high-wear-resistant tungsten steel alloy of the present invention include WC, Al-Sn-B nano-oxide and SiN / GO toughening phase. The tungsten steel alloy is designed into a gradient structure, the surface layer has hardness and wear resistance, and the internal layer has good fracture toughness. WC is the main hard phase in the tungsten steel alloy, providing extremely high hardness and wear resistance. The addition of Al-Sn-B nano-oxide can form a sintering aid, enhance the diffusion and mass transfer process of WC in high-temperature solid-phase sintering, thereby accelerating the densification of the tungsten steel alloy. The addition of SiN / GO toughening phase utilizes the graphene toughening mechanism to improve the fracture toughness of the tungsten steel alloy, so that the high-wear-resistant tungsten steel alloy prepared by the present invention has excellent wear resistance and high-temperature oxidation resistance, good toughness, strength and bending resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of cemented carbide, and particularly relates to a high-wear-resistant tungsten steel alloy and a preparation method thereof. Background Art

[0002] Tungsten carbide-cobalt (WC-Co) cemented carbide has good comprehensive mechanical properties and is widely used in the production of cutting tools, precision molds, wear-resistant parts and other products. However, with the complexity and extreme nature of the machining industry environment, its disadvantages such as poor corrosion resistance and low high-temperature hardness have gradually been exposed. Among them, the preferential corrosion, softening and wear of the binder phase are the main reasons for the reduction of product working accuracy and shortened service life. In addition, metal Co resources are relatively scarce. Compared with traditional WC-Co cemented carbide, WC cemented carbide without a binder phase has excellent wear resistance, oxidation resistance, corrosion resistance and polishing properties. Therefore, the research and development of tungsten carbide without a binder phase has become one of the hot topics in the cemented carbide field.

[0003] Although existing tungsten steel alloys perform well in many industrial applications, their wear resistance is still insufficient under some extreme wear conditions, such as high-speed cutting and high-load grinding, resulting in a short service life. In addition, it is often difficult to achieve a balance between hardness and toughness during the preparation process of existing tungsten steel alloys. Increasing the hardness often leads to a decrease in toughness, and vice versa. In the existing preparation method, the microstructure uniformity of the alloy is poor, which affects its overall wear resistance. Therefore, there is an urgent need to develop a highly wear-resistant tungsten steel alloy that can significantly improve wear resistance while maintaining a high hardness, while optimizing the balance between hardness and toughness. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention proposes a high-wear-resistant tungsten steel alloy and a preparation method thereof. The present invention adopts WC, Al-Sn-B nano-oxide and SiN / GO toughening phase to design and prepare the high-wear-resistant tungsten steel alloy. The tungsten steel alloy is designed into a gradient structure, with the surface layer having hardness and wear resistance and the inner layer having good toughness. WC is the main hard phase in the tungsten steel alloy, providing extremely high hardness and wear resistance. The addition of TiC further improves the wear resistance. The addition of Al-Sn-B nano-oxide can form a liquid-phase sintering aid, enhancing the diffusion and mass transfer process of the composite material during high-temperature solid-phase sintering, thereby accelerating densification. The addition of SiN / GO toughening phase utilizes the graphene toughening mechanism to improve the strength and toughness of the tungsten steel alloy. The addition of V, Mn and Mo improves the hardness and wear resistance of the tungsten steel alloy, so that the high-wear-resistant tungsten steel alloy prepared by the present invention has excellent wear resistance and high-temperature oxidation resistance, good toughness, strength and bending resistance.

[0005] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0006] The invention provides a high-wear-resistant tungsten steel alloy, which is composed of the following raw materials in parts by weight: 86-92 parts of WC, 1-2.5 parts of TiC, 1-5 parts of Al-B-Sn nano-oxide, 0.5-1.2 parts of V, 1.2-2 parts of Mn, 0.2-1 part of Mo, 0.5-1.5 parts of inhibitor, 0.1-1 part of forming agent, and 1-3 parts of SiN / GO (silicon nitride / graphene oxide) toughening phase;

[0007] Preferably, the inhibitor is prepared by mixing VC and Cr3C2, with a mass ratio of 1:0.6;

[0008] Preferably, the molding agent is polyvinyl alcohol;

[0009] The raw materials for preparing the Al-B-Sn nano-oxide are: Al(NO3)3·9H2O, acetylacetone, SnO2 and H3BO3;

[0010] The preparation method of the Al-B-Sn nano-oxide specifically comprises the following steps:

[0011] (1) Weigh Al(NO3)3·9H2O and dissolve it in ethylene glycol. Add acetylacetone and stir at 60°C for 2 h. Add SnO2 and stir to form a mixed solution.

[0012] (2) adding H3BO3 to the mixed solution obtained in step (1) and stirring at a constant temperature for 1 hour to obtain a precursor mixed solution;

[0013] (3) The precursor mixed solution was aged for 48 h to obtain a sol, and then the sol was placed in a muffle furnace for calcination. At room temperature, it was heated from room temperature to 300 ° C at 3 ° C / min, and kept warm for 2 h, and cooled to room temperature to obtain Al-B-Sn nano-oxide.

[0014] Furthermore, the usage ratio of Al(NO3)3·9H2O, SnO2, acetylacetone and ethylene glycol is 1-2g:0.5g:5mL:30mL.

[0015] Furthermore, the usage ratio of H3BO3 to the mixed solution is 0.1-0.3 g:30 mL.

[0016] The raw materials for preparing the SiN / GO toughening phase are: graphite powder, sodium nitrate and potassium permanganate;

[0017] The SiN / GO toughening phase preparation method specifically comprises the following steps:

[0018] (a) Concentrated sulfuric acid was added to a beaker, and graphite powder, sodium nitrate, and potassium permanganate were slowly added thereto. The mixture was placed in a water bath at 15°C for 3 h and then stirred at 35°C for 60 min using a thermostatic stirrer to form a mixed solution.

[0019] (b) adding 30% hydrogen peroxide to the mixed solution obtained in step (a) in a volume ratio of 1:3, reacting until no bubbles are generated in the beaker, stirring at a constant speed at room temperature for 60 minutes, washing with deionized water 3-5 times, diluting with 0.01M dilute hydrochloric acid to a pH of 7, and drying in a vacuum drying oven at 75°C for 12 hours to obtain GO brown powder;

[0020] (c) The brown GO powder prepared in step (b) was dissolved in a THF (tetrahydrofuran) solution, SiN was added, stirred evenly, and calcined. The mixture was heated to 400-600°C at a rate of 12°C / min at room temperature and maintained at 400-600°C for 2-4 hours to form a SiN / GO toughening phase.

[0021] Furthermore, the usage ratio of the graphite powder, sodium nitrate, potassium permanganate and concentrated sulfuric acid is 1g:0.6g:3g:25mL.

[0022] Furthermore, the usage ratio of the SiN and GO brown powders to THF is 0.5-1 g:1 g:15 mL.

[0023] The present invention also provides a method for preparing a high wear-resistant tungsten steel alloy, which specifically comprises the following steps:

[0024] S1, weighing 10-20 parts of anhydrous ethanol, adding SiN / GO toughening phase, V and Mo according to weight parts to the anhydrous ethanol and mixing evenly to obtain a mixture, placing the mixture in a wet mill and ball milling for 24 hours, and passing through a 400-500 mesh sieve to obtain a toughening slurry;

[0025] S2, drying the toughening slurry obtained in step S1, pressing and forming a green compact, placing the green compact in a high vacuum tube furnace for vacuum sintering, raising the sintering temperature from room temperature to 900-1100° C. in a nitrogen atmosphere, and maintaining the temperature at 900-1100° C. for 0.5-1 hour to obtain a toughening layer;

[0026] S3, weighing 80-100 parts of acetone, adding WC, TiC, Al-B-Sn nano-oxide, Mn and inhibitor according to weight parts to the acetone and mixing to form a mixed slurry, adding a forming agent according to weight parts to the mixed slurry, ball milling, and drying to obtain a powder;

[0027] S4, covering the toughening layer obtained in step S2 with the powder obtained in step S3, pressing into shape, and vacuum sintering. In a nitrogen atmosphere, the temperature is rapidly increased from room temperature to 1200°C at a heating rate of 20°C / min, maintained at 1200°C for 0.5-1h, then increased from 1200°C to 1400°C at a heating rate of 10°C / min, maintained at 1400°C for 0.5-1h, and cooled to obtain a high wear-resistant tungsten steel alloy.

[0028] Furthermore, the model of the wet grinding mill is 750×1060, and the model of the vacuum tube furnace is MXG1750-60.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention adopts WC, Al-Sn-B nano-oxide and SiN / GO toughening phase to design and prepare high-wear-resistant tungsten steel alloy. The tungsten steel alloy is designed to have a gradient structure, the surface layer has hardness and wear resistance, and the internal layer has good toughness. WC is the main hard phase of the tungsten steel alloy and provides extremely high hardness and wear resistance. The addition of TiC further improves the wear resistance. The addition of Al-Sn-B nano-oxide can form a liquid-phase sintering aid, thereby enhancing the diffusion and mass transfer process of the tungsten steel alloy in high-temperature solid-phase sintering, thereby accelerating densification. The SiN / GO toughening phase utilizes the graphene toughening mechanism to improve the fracture toughness of the tungsten steel alloy. V, Mn and Mo improve the hardness and wear resistance of the tungsten steel alloy. The addition of Mn improves the bending strength of the tungsten steel alloy, making the tungsten steel alloy less likely to break. The addition of V improves the oxidation resistance of the tungsten steel alloy at high temperatures, thereby enabling the tungsten steel alloy to work normally at high temperatures. Al-Sn-B nano-oxide and WC jointly increase the hardness of tungsten steel alloy, because nano-particles can act as hard phase reinforcement materials, improve the wear resistance of the alloy, and increase the density of tungsten steel alloy. The high hardness and small size of Al-Sn-B nano-oxide can reduce plowing and cutting during the wear process, thereby improving the wear resistance of tungsten steel alloy. Al-Sn-B nano-oxide can form a protective oxide film at high temperature, which helps to prevent further oxidation of tungsten steel alloy in high temperature environment. Al-Sn-B nano-oxide can enhance the corrosion resistance of tungsten steel alloy, refine the grains of tungsten steel alloy, thereby optimizing its microstructure, and make the prepared high wear-resistant tungsten steel alloy have ultrafine grain size. Al-Sn-B nano-oxide can act as a sintering aid to promote the sintering process of other components in tungsten steel alloy, reduce the sintering temperature, shorten the sintering time, and improve the density and integrity of the material. GO possesses extremely high strength and excellent fracture toughness. Its two-dimensional layered structure effectively hinders crack propagation in tungsten steel alloys, significantly improving their toughness. The addition of GO improves the tensile, compressive, and flexural strengths of tungsten steel alloys, resulting in better overall performance under mechanical loads. The addition of Al-Sn-B nano-oxides helps reduce cracks and pores in tungsten steel alloys. GO further reduces fatigue crack propagation under cyclic loading, improving fatigue life. SiN possesses high thermal stability and excellent high-temperature mechanical properties. When combined with GO, it can maintain the structural integrity and toughness of tungsten steel alloys at high temperatures. SiN forms a dense oxide film at high temperatures, protecting the underlying material from further oxidation. Combining with GO further enhances the alloy's oxidation resistance. Combined with the oxide film formed by the Al-Sn-B nano-oxides, it exhibits excellent stability at high temperatures. SiN itself possesses excellent wear resistance. When combined with GO, it further improves the wear resistance of tungsten steel alloys while maintaining toughness.Using VC and Cr3C2 as inhibitors not only inhibits WC grain growth and maintains a uniform and fine grain size, but the VC phase also enhances the wear resistance of the tungsten steel alloy. The added V also generates a VC phase at high temperatures, enhancing the alloy's wear resistance. The high-wear-resistant tungsten steel alloy prepared by the present invention has excellent wear resistance and high-temperature oxidation resistance, good toughness, strength, and bending resistance, high hardness, high density, and a fine and uniform structure, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a fracture morphology diagram of the high wear-resistant tungsten steel alloy prepared by the present invention;

[0032] Figure 2 Schematic diagram of the average grain size of the high wear-resistant tungsten steel alloy prepared in the present invention;

[0033] Figure 3 Schematic diagram of the wear weight loss of the high wear-resistant tungsten steel alloy prepared in the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention and to make the above-mentioned features, purposes and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with examples. The examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0035] It should be noted that, unless otherwise specified, all chemical reagents involved in the present invention were purchased through commercial channels.

[0036] Example 1: This example provides a high wear-resistant tungsten steel alloy, which is composed of the following raw materials in parts by weight: 86 parts of WC, 1 part of TiC, 5 parts of Al-B-Sn nano-oxide, 0.5 parts of V, 1.2 parts of Mn, 0.2 parts of Mo, 0.5 parts of inhibitor, 4 parts of forming agent, and 1 part of SiN / GO toughening phase;

[0037] The inhibitor is prepared by mixing VC and Cr3C2, with a mass ratio of 1:0.6;

[0038] The forming agent is polyvinyl alcohol;

[0039] The raw materials for preparing the Al-B-Sn nano-oxide are: Al(NO3)3·9H2O, acetylacetone, SnO2 and H3BO3;

[0040] The preparation method of the Al-B-Sn nano-oxide specifically comprises the following steps:

[0041] (1) Weigh Al(NO3)3·9H2O and dissolve it in ethylene glycol. Add acetylacetone and stir at 60°C for 2 h. Add SnO2 in a ratio of 1 g:0.5 g:5 mL:30 mL to form a mixed solution.

[0042] (2) adding H3BO3 to the mixed solution obtained in step (1) at a ratio of H3BO3 to the mixed solution of 0.1 g:30 mL, and stirring at a constant temperature for 1 h to obtain a precursor mixed solution;

[0043] (3) The precursor mixed solution was aged for 48 h to obtain a sol, and then the sol was placed in a muffle furnace for calcination. At room temperature, it was heated from room temperature to 300 ° C at 3 ° C / min, and maintained at 300 ° C for 2 h, and cooled to room temperature to obtain Al-B-Sn nano-oxide.

[0044] The raw materials for preparing the SiN / GO toughening phase are: graphite powder, sodium nitrate and potassium permanganate;

[0045] The preparation method of the SiN / GO toughening phase specifically comprises the following steps:

[0046] (a) Concentrated sulfuric acid was added to a beaker, and graphite powder, sodium nitrate, and potassium permanganate were slowly added in a ratio of 1 g:0.6 g:3 g:25 mL. The mixture was placed in a water bath at 15°C for 3 h. The mixture was then stirred at 300 rpm for 60 min at 35°C using a thermostatic stirrer to form a mixed solution.

[0047] (b) adding 30% hydrogen peroxide to the mixed solution obtained in step (a) in a volume ratio of 1:3, and reacting until no bubbles are generated in the beaker, then stirring at 200 rpm for 60 min at room temperature, washing with deionized water five times, and then diluting with 0.01 M dilute hydrochloric acid to a pH of 7, and drying in a vacuum drying oven at 75°C for 12 h to obtain GO brown powder;

[0048] (c) The GO brown powder prepared in step (b) was dissolved in THF, and SiN was added in a ratio of 0.5 g SiN to GO brown powder to THF:1 g:15 mL. The mixture was stirred at 180 rpm and calcined by heating to 400°C at a rate of 12°C / min at room temperature and maintaining at 400°C for 2 h to form a SiN / GO toughening phase.

[0049] This embodiment also provides a method for preparing a high wear-resistant tungsten steel alloy, which specifically includes the following steps:

[0050] S1, weighing 10 parts of anhydrous ethanol, adding 1 part of SiN / GO toughening phase, 0.5 parts of V and 1.3 parts of Mo to the anhydrous ethanol and mixing evenly to obtain a mixture, placing the mixture in a wet mill and ball milling for 24 hours, and passing through a 400-mesh sieve to obtain a toughening slurry;

[0051] S2, drying the toughening slurry obtained in step S1, pressing and forming a green compact, and vacuum sintering the green compact in a vacuum tube furnace. In a nitrogen atmosphere, the sintering temperature is raised from room temperature to 900° C. and maintained at 900° C. for 0.5 h to form a toughening layer.

[0052] S3, weighing 80 parts of acetone, adding 86 parts of WC, 1 part of TiC, 5 parts of Al-B-Sn nano-oxide, 0.2 parts of Mn and 0.5 parts of inhibitor to the acetone to form a mixed slurry, adding 4 parts of a forming agent to the mixed slurry, ball milling, and drying to obtain a powder;

[0053] S4, covering the toughening layer obtained in step S2 with the powder obtained in step S3, pressing into shape, and vacuum sintering. In a nitrogen atmosphere, the temperature is rapidly increased from room temperature to 1200°C at a heating rate of 20°C / min, maintained at this temperature for 0.5h, then increased from 1200°C to 1400°C at a heating rate of 10°C / min, and maintained at 1400°C for 0.5h. After cooling, a high wear-resistant tungsten steel alloy is obtained.

[0054] Example 2: This example provides a high wear-resistant tungsten steel alloy, which is composed of the following raw materials in percentage by mass: 89 parts of WC, 1.8 parts of TiC, 3 parts of Al-B-Sn nano-oxide, 1 part of V, 1.6 parts of Mn, 0.8 parts of Mo, 1 part of inhibitor, 5 parts of forming agent, and 2 parts of SiN / GO toughening phase;

[0055] The inhibitor is prepared by mixing VC and Cr3C2, with a mass ratio of 1:0.6;

[0056] The forming agent is polyvinyl alcohol;

[0057] The raw materials for preparing the Al-B-Sn nano-oxide are: Al(NO3)3·9H2O, acetylacetone, SnO2 and H3BO3;

[0058] The preparation method of the Al-B-Sn nano-oxide specifically comprises the following steps:

[0059] (1) Weigh Al(NO3)3·9H2O and dissolve it in ethylene glycol. Add acetylacetone and stir at 60°C for 2 h. Add SnO2 in a ratio of 1.5 g:0.5 g:5 mL:30 mL to form a mixed solution.

[0060] (2) adding H3BO3 to the mixed solution obtained in step (1) at a ratio of 0.2 g:30 mL of H3BO3 to the mixed solution, and stirring at a constant temperature for 1 h to obtain a precursor mixed solution;

[0061] (3) The precursor mixed solution was aged for 48 h to obtain a sol, and then the sol was placed in a muffle furnace for calcination. At room temperature, it was heated from room temperature to 300 ° C at 3 ° C / min, and maintained at 300 ° C for 2 h, and cooled to room temperature to obtain Al-B-Sn nano-oxide.

[0062] The raw materials for preparing the SiN / GO toughening phase are: graphite powder, sodium nitrate and potassium permanganate;

[0063] The preparation method of the SiN / GO toughening phase specifically comprises the following steps:

[0064] (a) Concentrated sulfuric acid was added to a beaker, and graphite powder, sodium nitrate, and potassium permanganate were slowly added in a ratio of 1 g:0.6 g:3 g:25 mL. The mixture was placed in a water bath at 15°C for 3 h. The mixture was then stirred at 300 rpm for 60 min at 35°C using a thermostatic stirrer to form a mixed solution.

[0065] (b) adding 30% hydrogen peroxide to the mixture obtained in step (a) in a volume ratio of 1:3, and reacting until no bubbles are generated in the beaker, then stirring at 200 rpm for 60 min at room temperature, washing with deionized water five times, diluting with 0.01 M dilute hydrochloric acid to a pH of 7, and drying in a vacuum drying oven at 75°C for 12 h to obtain GO brown powder;

[0066] (c) The GO brown powder prepared in step (b) was dissolved in a THF solution, and SiN was added at a ratio of 0.8 g SiN, GO brown powder, and THF of 1 g to 15 mL. The mixture was stirred at 180 rpm and calcined by heating to 500°C at a rate of 12°C / min at room temperature and maintaining at 500°C for 3 h to form a SiN / GO toughening phase.

[0067] This embodiment also provides a method for preparing a high wear-resistant tungsten steel alloy, which specifically includes the following steps:

[0068] S1, weighing 15 parts of anhydrous ethanol, adding 2 parts of SiN / GO toughening phase, 1 part of V and 0.8 parts of Mo to the anhydrous ethanol and mixing evenly to obtain a mixture, placing the mixture in a wet mill and ball milling for 24 hours, and passing through a 450 mesh sieve to obtain a toughening slurry;

[0069] S2, drying the toughening slurry obtained in step S1, pressing the toughening slurry into a compact, placing the compact into a vacuum tube furnace for vacuum sintering, raising the sintering temperature from room temperature to 1000° C. in a nitrogen atmosphere, and maintaining the temperature at 1000° C. for 0.8 h to obtain a toughening layer;

[0070] S3, weighing 80-100 parts of acetone, adding 89 parts of WC, 1.8 parts of TiC, 3 parts of Al-B-Sn nano-oxide, 1.6 parts of Mn and 1 part of inhibitor to the acetone to form a mixed slurry, adding a forming agent to the mixed slurry, ball milling, and drying to obtain a powder;

[0071] S4, covering the toughening layer obtained in step S2 with the powder obtained in step S3, pressing into shape, and vacuum sintering. In a nitrogen atmosphere, the temperature is rapidly increased from room temperature to 1200°C at a heating rate of 20°C / min, maintained at 1200°C for 0.8h, then increased from 1200°C to 1400°C at a heating rate of 10°C / min, and maintained at 1400°C for 0.8h. After cooling, a high wear-resistant tungsten steel alloy is obtained.

[0072] Example 3: This example provides a high wear-resistant tungsten steel alloy, which is composed of the following raw materials in parts by weight: 92 parts of WC, 2.5 parts of TiC, 1 part of Al-B-Sn nano-oxide, 1.2 parts of V, 2 parts of Mn, 1 part of Mo, 1.5 parts of inhibitor, 6 parts of forming agent, and 3 parts of SiN / GO toughening phase;

[0073] The inhibitor is prepared by mixing VC and Cr3C2, with a mass ratio of 1:0.6;

[0074] The forming agent is polyvinyl alcohol;

[0075] The raw materials for preparing the Al-B-Sn nano-oxide are: Al(NO3)3·9H2O, acetylacetone, SnO2 and H3BO3;

[0076] The preparation method of the Al-B-Sn nano-oxide specifically comprises the following steps:

[0077] (1) Weigh Al(NO3)3·9H2O and dissolve it in ethylene glycol. Add acetylacetone and stir at 60°C for 2 h. Add SnO2 in a ratio of 2 g:0.5 g:5 mL:30 mL of Al(NO3)3·9H2O, SnO2, acetylacetone, and ethylene glycol. Stir and mix to form a mixed solution.

[0078] (2) adding H3BO3 to the mixed solution obtained in step (1) at a ratio of 0.3 g:30 mL of H3BO3 to the mixed solution, and stirring at a constant temperature for 1 h to obtain a precursor mixed solution;

[0079] (3) The precursor mixed solution was aged for 48 h to obtain a sol, which was then placed in a muffle furnace for calcination. At room temperature, the sol was heated from room temperature to 300 °C at a rate of 3 °C / min, maintained at 300 °C for 2 h, and cooled to room temperature to obtain Al-B-Sn nano-oxide.

[0080] The raw materials for preparing the SiN / GO toughening phase are: graphite powder, sodium nitrate and potassium permanganate;

[0081] The preparation method of the SiN / GO toughening phase specifically comprises the following steps:

[0082] (a) Concentrated sulfuric acid was added to a beaker, and graphite powder, sodium nitrate, and potassium permanganate were slowly added in a ratio of 1 g:0.6 g:3 g:25 mL. The mixture was placed in a water bath at 15°C for 3 h and then stirred at 35°C for 60 min using a thermostatic stirrer to form a mixed solution.

[0083] (b) adding 30% hydrogen peroxide to the mixture obtained in step (a) in a volume ratio of 1:3, and reacting until no bubbles are generated in the beaker, then stirring at 200 rpm for 60 min at room temperature, washing with deionized water five times, diluting with 0.01 M dilute hydrochloric acid to a pH of 7, and drying in a vacuum drying oven at 75°C for 12 h to obtain GO brown powder;

[0084] (c) The GO brown powder prepared in step (b) was dissolved in a THF solution, and SiN was added in a ratio of 1 g SiN to GO brown powder to THF of 1 g:1 g:15 mL. The mixture was stirred at 180 rpm and calcined by heating to 600°C at a rate of 12°C / min at room temperature and maintaining at 600°C for 4 h to form a SiN / GO toughening phase.

[0085] This embodiment also provides a method for preparing a high wear-resistant tungsten steel alloy, which specifically includes the following steps:

[0086] S1: Weigh 20 parts of anhydrous ethanol, add 3 parts of SiN / GO toughening phase, 1.2 parts of V, and 1 part of Mo into the anhydrous ethanol and mix well to obtain a mixture. Place the mixture in a wet grinder and ball mill for 24 hours. Then pass it through a 500-mesh sieve to obtain a toughening slurry.

[0087] S2, drying the toughening slurry obtained in step S1, pressing the toughening slurry into a compact, and placing the compact into a vacuum tube furnace for sintering. In a nitrogen atmosphere, the sintering temperature is raised from room temperature to 1100° C. and maintained at 1100° C. for 1 hour to obtain a toughening layer.

[0088] S3, weighing 100 parts of acetone, adding 92 parts of WC, 2.5 parts of TiC, 1 part of Al-B-Sn nano-oxide, 2 parts of Mn and 1.5 parts of inhibitor to the acetone to form a mixed slurry, adding a forming agent to the mixed slurry, ball milling, and drying to obtain a powder;

[0089] S4, covering the toughening layer obtained in step S2 with the powder obtained in step S3, pressing into shape, and vacuum sintering. In a nitrogen atmosphere, the temperature is rapidly increased from room temperature to 1200°C at a heating rate of 20°C / min, maintained at 1200°C for 1 hour, then increased from 1200°C to 1400°C at a heating rate of 10°C / min, and maintained at 1400°C for 1 hour. After cooling, a high wear-resistant tungsten steel alloy is obtained.

[0090] The difference between Comparative Example 1 and Example 1 is that the addition of Al-B-Sn nano-oxide is omitted, and the rest is the same as Example 1.

[0091] The difference between Comparative Example 2 and Example 1 is that the addition of SiN / GO toughening phase is omitted, and the rest is the same as Example 1.

[0092] The difference between Comparative Example 3 and Example 1 is that the preparation method of the high wear-resistant tungsten steel alloy is as follows: SiN / GO toughening phase is weighed and mixed with V and Mo in anhydrous ethanol by weight to obtain a mixture, the mixture is placed in a wet grinder for ball milling for 24 hours, and passed through a 400-500 mesh sieve to obtain a toughening slurry; WC, TiC, Al-B-Sn nanooxide, Mn, and inhibitor are mixed by weight, added to the toughening slurry and mixed evenly, acetone is added to form a mixed slurry, a forming agent is added to the mixed slurry, ball milled, and dried to obtain a powder; the powder is pressed into shape and vacuum sintered. In a nitrogen atmosphere, the temperature is rapidly increased from room temperature to 1200°C at a heating rate of 20°C / min, maintained at 1200°C for 0.5-1h, then increased from 1200°C to 1400°C at a heating rate of 10°C / min, and maintained at 1400°C for 0.5-1h, and cooled to obtain a high wear-resistant tungsten steel alloy.

[0093] Experimental Example 1: According to GB / T 230.3-2022 "Rockwell Hardness Test for Metallic Materials", the hardness of the high wear-resistant tungsten steel alloy prepared by the present invention was tested. The tungsten steel alloys prepared in Example 1-3 and Comparative Example 3 were used as samples. The Rockwell hardness was tested using a D-150 Rockwell hardness tester. After being made into a standard sample by wire cutting, the sample was placed on a sample table for marking. Five points were selected for each sample, and the average value was finally calculated. The calculated results are recorded in Table 1.

[0094] Experimental Example 2: A rubber wheel wear tester (MLG-130) was used to conduct an abrasive wear test on the sample. The high wear-resistant tungsten steel alloy prepared in Examples 1-3 and Comparative Examples 1-3 was used as a wear sample, and the size of the wear sample was 57mm×25.5mm×6mm. Quartz sand of 212-270μm was used as the abrasive. During the experiment, the flow rate of the abrasive was 300g / min, the speed of the rubber wheel was 200r / min, and the wear load was 130N. In order to ensure the accuracy of the wear results, the sample was pre-ground for 10 minutes before the formal wear to reduce the experimental error. After the formal wear was completed, the wear sample was rinsed with alcohol and cleaned with ultrasonic oscillation for 10 minutes to remove the abrasive debris on the wear surface. It was then weighed with an electronic balance. The wear mass loss was calculated based on the mass difference of the sample before and after wear. The total wear time was 120 minutes, and the wear weight loss was measured every 30 minutes. The wear weight loss results are as follows: Figure 2 shown.

[0095] Experimental Example 3: The fracture toughness of the tungsten steel alloy prepared in this invention was tested according to JB / T 12616-2016, "Test Method for Fracture Toughness of Cemented Carbide Tool Matrix Materials." The sample surface was ground to a thickness of 0.2 mm. During sample preparation, the effects of heat and cold working on the sample surface hardness should be avoided. The test surface and the corresponding support surface of the sample should be parallel to each other. The sample was fixed on a fracture toughness testing machine, ensuring that the crack tip was located below the loading point. The sample was loaded at a rate of 0.1 mm / min. During the loading process, the load and crack tip displacement or sample bending deflection were continuously recorded. When the load reached its maximum value or began to decrease, the loading was stopped, and the fracture toughness was calculated based on the recorded data. The results are recorded in Table 1.

[0096] Table 1

[0097]

[0098] Experimental Example 4: Flexural strength was tested according to YB / T 5349-2014, "Test Methods for Bending Mechanical Properties of Metallic Materials." The wear-resistant tungsten steel alloys prepared in Examples 1-3 and Comparative Examples 1-3 were used as specimens, shaped into 15×10×180 mm rectangular strips. An MTS-809 electro-hydraulic servo universal testing machine was used. Before testing, the width and height of each specimen were measured and recorded. The three-point bending test apparatus was then installed and the span adjusted. The specimens were placed symmetrically and steadily on two support rollers. The test was initiated and continuously loaded at a stress rate of 5 MPa / s until fracture. The flexural strength was calculated and the results are recorded in Table 1.

[0099] The results in Table 1 show that the hardness of the high wear-resistant tungsten steel alloy prepared by the present invention is higher than that of the comparative examples 1-3, indicating that the high wear-resistant tungsten steel alloy prepared by the present invention has high hardness. The fracture toughness results show that the high wear-resistant tungsten steel alloy prepared by the present invention reaches 16.2 MPa·m 1 / 2 , indicating that the added toughening layer plays a good role, making the prepared high wear-resistant tungsten steel alloy have high fracture toughness. The bending strength results further show that the high wear-resistant tungsten steel alloy prepared by the present invention has excellent wear resistance and high temperature oxidation resistance, good toughness, strength and bending resistance.

[0100] Figure 1 The results show that the prepared high wear-resistant tungsten steel alloy has a uniform microstructure with a grain size of about 200nm. Figure 2 It can be seen that the average grain size of the high wear-resistant tungsten steel alloy prepared by the present invention is less than 0.5 μm, and it has ultrafine grains, which shows that the nano-oxides and inhibitors added in the present invention play a good role in obtaining a dense and fine-grained tungsten steel alloy, thereby enhancing the wear resistance of the tungsten steel alloy. Figure 3 The results show that the wear weight loss of the high wear-resistant tungsten steel alloy prepared by the present invention is significantly lower than that of the comparative example, indicating that the high wear-resistant tungsten steel alloy prepared by the present invention has excellent wear resistance.

[0101] In summary, through the verification of experimental examples and comparative examples, it can be seen that the addition of Al-B-Sn nano-oxide helps to refine the grains of tungsten steel alloy, making the microstructure more fine and uniform. This uniform and fine microstructure not only improves the mechanical properties of the material, but also enhances its thermal stability and corrosion resistance. The addition of SiN / GO toughening phase, the introduction of this toughening phase significantly improves the fracture toughness of tungsten steel alloy. When subjected to impact or vibration loads, the alloy exhibits better resistance to crack propagation, thereby improving the reliability and service life of the material. Through the design of toughening phase and hard phase, the present invention achieves a good balance of hardness, wear resistance, density and fracture toughness. This improvement in comprehensive performance enables tungsten steel alloy to exhibit excellent performance in a variety of application scenarios, including but not limited to cutting tools, mold manufacturing, wear-resistant parts and other fields, and has broad application prospects.

[0102] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A high wear-resistant tungsten steel alloy, characterized in that: The high wear-resistant tungsten steel alloy is composed of the following raw materials in parts by weight: 86-92 parts of WC, 1-2.5 parts of TiC, 1-5 parts of Al-B-Sn nano-oxide, 0.5-1.2 parts of V, 1.2-2 parts of Mn, 0.2-1 parts of Mo, 0.5-1.5 parts of inhibitor, 4-6 parts of forming agent, and 1-3 parts of SiN / GO toughening phase; The inhibitor is prepared by mixing VC and Cr3C2, with a mass ratio of 1:0.6; The forming agent is polyvinyl alcohol; The raw materials for preparing the Al-B-Sn nano-oxide are: Al(NO3)3·9H2O, acetylacetone, SnO2 and H3BO3; The preparation method of the Al-B-Sn nano-oxide specifically comprises the following steps: (1) Weigh Al(NO3)3·9H2O and dissolve it in ethylene glycol. Add acetylacetone and stir at constant temperature. Add SnO2 and stir to form a mixed solution. (2) adding H3BO3 to the mixed solution obtained in step (1) and stirring at a constant temperature to obtain a precursor mixed solution; (3) aging the precursor mixed solution to obtain a sol, calcining it, and cooling it to room temperature to obtain Al-B-Sn nano-oxide; The preparation method of the high wear-resistant tungsten steel alloy specifically comprises the following steps: S1, weighing 10-20 parts of anhydrous ethanol, adding SiN / GO toughening phase, V and Mo according to parts by weight to the anhydrous ethanol and mixing evenly to obtain a mixture, placing the mixture in a wet grinder for ball milling, and sieving to form a toughening slurry; S2, drying the toughening slurry obtained in step S1, pressing and forming the toughening slurry to obtain a compact, and vacuum sintering the compact to obtain a toughening layer; S3, weighing 80-100 parts of acetone, adding WC, TiC, Al-B-Sn nano-oxide, Mn and inhibitor according to weight parts to the acetone to form a mixed slurry, adding a forming agent to the mixed slurry, ball milling, and drying to obtain a powder; S4, covering the toughening layer obtained in step S2 with the powder obtained in step S3, pressing and forming, vacuum sintering, and cooling to obtain a high wear-resistant tungsten steel alloy.

2. A high wear-resistant tungsten steel alloy according to claim 1, characterized in that: In step (1), the usage ratio of Al(NO3)3·9H2O, SnO2, acetylacetone and ethylene glycol is 1-2 g:0.5 g:5 mL:30 mL.

3. The high wear-resistant tungsten steel alloy according to claim 1, characterized in that: In step (2), the ratio of H3BO3 to the mixed solution is 0.1-0.3 g:30 mL.

4. The high wear-resistant tungsten steel alloy according to claim 1, characterized in that: The raw materials for preparing the SiN / GO toughening phase are: graphite powder, sodium nitrate and potassium permanganate; The preparation method of the SiN / GO toughening phase specifically comprises the following steps: (a) Slowly add graphite powder, sodium nitrate, and potassium permanganate to concentrated sulfuric acid, place in a water bath, and stir at a constant temperature to form a mixed solution; (b) adding 30% hydrogen peroxide to the mixture obtained in step (a) and reacting until no bubbles are generated, followed by stirring at room temperature, washing with deionized water, and then diluting with 0.01 M dilute hydrochloric acid to a pH of 7, and drying to obtain GO brown powder; (c) The GO brown powder prepared in step (b) was dissolved in THF, SiN was added, stirred evenly, and calcined to form a SiN / GO toughening phase.

5. A high wear-resistant tungsten steel alloy according to claim 4, characterized in that: In step (a), the amount ratio of the graphite powder, sodium nitrate, potassium permanganate and concentrated sulfuric acid is 1 g:0.6 g:3 g:25 mL. In step (b), the volume ratio of the hydrogen peroxide to the mixed solution is 1:

3. In step (c), the amount ratio of the SiN and GO brown powder to THF is 0.5-1 g:1 g:15 mL.

6. The high wear-resistant tungsten steel alloy according to claim 1, characterized in that: In step S2, the vacuum sintering is performed in a nitrogen atmosphere by raising the sintering temperature from room temperature to 900-1100°C and maintaining the temperature at 900-1100°C for 0.5-1 h.

7. The high wear-resistant tungsten steel alloy according to claim 1, characterized in that: In step S4, the vacuum sintering is carried out in a nitrogen atmosphere by rapidly raising the temperature from room temperature to 1200°C at a heating rate of 20°C / min, maintaining at 1200°C for 0.5-1 h, then raising the temperature from 1200°C to 1400°C at a heating rate of 10°C / min, and maintaining at 1400°C for 0.5-1 h.

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