High-toughness wear-resistant tungsten carbide alloy and preparation method thereof

Abstract

A high-toughness wear-resistant tungsten carbide alloy and a preparation method thereof, belonging to the technical field of tungsten alloys. The preparation method of the high-toughness wear-resistant tungsten carbide alloy comprises the following steps: adding tungsten carbide powder and metal cobalt powder into a ball mill, adding anhydrous ethanol, and ball milling to obtain a mixed slurry; vacuum drying the mixed slurry, sieving, and obtaining tungsten carbide-cobalt powder; placing the tungsten carbide-cobalt powder in a mold, and performing compression molding to obtain a pressed blank; placing the pressed blank in a vacuum sintering furnace, and sequentially performing primary sintering, secondary sintering, and tertiary sintering, and the sintered blank is naturally cooled to room temperature to obtain a high-toughness wear-resistant tungsten carbide alloy. The grain size of the tungsten carbide alloy described in the present invention is small and evenly distributed, and has excellent wear resistance and toughness.

Description

Technical Field

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

[0002] Cemented carbide is a composite material prepared by traditional powder metallurgy method with high hardness refractory metal carbide powder as hard phase and metals such as Co and Ni as bonding phase. Cemented carbide is an indispensable key material in almost all industries and new technology fields, especially in aerospace, automobile, electronics, shipbuilding, mining, oil drilling and military industry. Among them, WC-Co cemented carbide with tungsten carbide as hard phase and Co as bonding phase is the most widely used cemented carbide at present. However, due to the homogeneity of composition and organization, there are sharp contradictions between various properties (such as strength and hardness, wear resistance and toughness), which greatly limits its industrial application. In addition, in the preparation process of cemented carbide, it is extremely difficult to control WC grains.

[0003] Patent CN112647006B discloses a tungsten carbide-based cemented carbide, including a tungsten carbide hard phase and a binder phase, wherein the binder phase is a high entropy alloy; the cemented carbide includes the following components by mass fraction: 90.38% tungsten carbide, 9.5% high entropy alloy, 0.06% yttrium and 0.06% lanthanum. Due to the addition of rare earth elements, its production cost is increased, and the comprehensive properties of the tungsten carbide alloy, such as bending strength, need to be further improved.

[0004] Patent CN116752024A discloses a tungsten carbide super wear-resistant hard alloy, including tungsten carbide powder 90-97wt%, rare earth metal 0.1-2.5wt%, limiter 0.1-2.3wt%, cobalt 0.1-1.3wt%, the limiter is a mixture of chromium and vanadium, the mass ratio is 0.5-1.5: 1. The wear resistance of the tungsten carbide is good, but the bending strength needs to be further improved. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a high-toughness wear-resistant tungsten carbide alloy and a preparation method thereof, wherein the tungsten carbide alloy has a small grain size and is evenly distributed, and has both excellent wear resistance and toughness.

[0006] In order to achieve the above object, according to one aspect of the present invention, a method for preparing a high-toughness wear-resistant tungsten carbide alloy is provided, comprising the following steps:

[0007] (1) Add tungsten carbide powder and metal cobalt powder into a ball mill, add anhydrous ethanol, and perform ball milling to obtain a mixed slurry;

[0008] (2) vacuum drying the mixed slurry and sieving it to obtain tungsten carbide-cobalt powder;

[0009] (3) placing the tungsten carbide-cobalt powder in a mold and performing compression molding to obtain a compact;

[0010] (4) Placing the pressed green sheet in a vacuum sintering furnace for primary sintering, secondary sintering and tertiary sintering in sequence. The sintered green sheet is naturally cooled to room temperature to obtain a high-toughness, wear-resistant tungsten carbide alloy.

[0011] In the present invention, the primary sintering temperature is 400-450° C., and the primary sintering time is 1-1.5 h.

[0012] In the present invention, the secondary sintering temperature is 900-950° C., and the secondary sintering time is 2-2.5 hours.

[0013] In the present invention, the temperature of the three sinterings is 1000-1100° C., and the time of the three sinterings is 1.5-2 hours.

[0014] In the present invention, in step (1), the tungsten carbide powder is a mixture of a first tungsten carbide powder with an average particle size of 0.85-0.95 μm and a second tungsten carbide powder with an average particle size of 1-1.5 μm, and the mass ratio of the first tungsten carbide powder to the second tungsten carbide powder is 2-3:1; the average particle size of the cobalt powder is 14-15 μm.

[0015] In the present invention, in step (1), the ball milling is carried out in an argon or nitrogen protective atmosphere, the rotation speed of the ball mill is 150-200 r / min, the ball-to-material ratio is 8-10:1, and the ball milling time is 24-36 h.

[0016] In the present invention, in step (3), the compression molding pressure is 100-300 MPa.

[0017] According to another aspect of the present invention, there is also provided a high-toughness wear-resistant tungsten carbide alloy prepared according to the above preparation method.

[0018] In the present invention, the tungsten carbide alloy comprises, by mass percentage, 80% tungsten carbide and 20% cobalt.

[0019] In the present invention, the density of the tungsten carbide alloy is 13.4-13.8 g / cm³, and the average particle size of the tungsten carbide grains is 1.4-1.8 μm.

[0020] The inventors of the present invention found that the sintering method has a great influence on the performance of tungsten carbide alloy. The inventors adjusted the conventional one-time sintering to three-time sintering, and further controlled the temperature and time of each sintering, so that the microstructure of the prepared tungsten carbide alloy was improved, the average size of the tungsten carbide grains was smaller, and the particle size distribution was more uniform, thereby significantly improving the wear resistance and toughness of the tungsten carbide alloy. The inventors also found that by selecting the tungsten carbide powder of the specific particle size described in the present invention for compounding, the two synergistically improved the microstructure of the tungsten carbide alloy, making the grain size of the tungsten carbide alloy more uniform and the porosity lower, thereby significantly improving the wear resistance and toughness of the tungsten carbide alloy. In addition, in step (3) of the present invention, the density distribution and strength of the pressed blank are further controlled by adjusting the molding pressure.

[0021] The tungsten carbide alloy prepared by the preparation method of the present invention has a large density, a high hardness, a small average grain size, and excellent wear resistance and toughness, thereby greatly improving the application range of the tungsten carbide alloy.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) By controlling the process conditions of the tungsten carbide alloy preparation process, especially the control of the temperature and time of the three sintering processes, the microstructure of the prepared tungsten carbide alloy is improved, the average size of the tungsten carbide grains is smaller, and the grain distribution is more uniform and compact, thereby significantly improving the wear resistance and toughness of the tungsten carbide alloy. In addition, the sintering method described in the present invention improves the fluidity of cobalt, so that cobalt is evenly distributed around the tungsten carbide, and also reduces the presence of pores, which is conducive to improving the density of the material.

[0023] (2) The present invention selects two tungsten carbide powders of specific particle sizes for compounding, and the two synergistically improve the microstructure of the tungsten carbide alloy, making the porosity of the tungsten carbide alloy lower, thereby significantly improving the wear resistance and toughness of the tungsten carbide alloy.

[0024] (3) The tungsten carbide alloy described in the present invention has a large density, high hardness, a small average grain size, and excellent wear resistance and toughness, which greatly improves the application range of the tungsten carbide alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings.

[0026] Figure 1 This is the metallographic structure diagram of the tungsten carbide alloy prepared in Example 1 of the present invention.

[0027] Figure 2 This is the metallographic structure diagram of the tungsten carbide alloy prepared in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0029] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0030] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0031] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0032] The present invention provides a method for preparing a high-toughness wear-resistant tungsten carbide alloy, comprising the following steps:

[0033] (1) Add tungsten carbide powder and metal cobalt powder into a ball mill, add anhydrous ethanol, and perform ball milling to obtain a mixed slurry;

[0034] (2) vacuum drying the mixed slurry and sieving it to obtain tungsten carbide-cobalt powder;

[0035] (3) placing the tungsten carbide-cobalt powder in a mold and performing compression molding to obtain a compact;

[0036] (4) Placing the pressed green sheet in a vacuum sintering furnace for primary sintering, secondary sintering and tertiary sintering in sequence. The sintered green sheet is naturally cooled to room temperature to obtain a high-toughness, wear-resistant tungsten carbide alloy.

[0037] In the present invention, in step (1), tungsten carbide powder and metal cobalt powder are added to a ball mill, anhydrous ethanol is added, and ball milling is performed to obtain a mixed slurry. In the present invention, the tungsten carbide powder is a mixture of a first tungsten carbide powder with an average particle size of 0.85-0.95 μm and a second tungsten carbide powder with an average particle size of 1-1.5 μm, and the mass ratio of the first tungsten carbide powder to the second tungsten carbide powder is 2-3:1. It can be understood that the average particle size of the first tungsten carbide powder can be any specific value of 0.85 μm, 0.86 μm, 0.87 μm, 0.88 μm, 0.89 μm, 0.9 μm, 0.91 μm, 0.92 μm, 0.93 μm, 0.94 μm, 0.95 μm, or any value within the range of 0.85-0.95 μm. It is understood that the average particle size of the second tungsten carbide powder can be any specific value of 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, or any value in the range of 1-1.5 μm. It is understood that the mass ratio of the first tungsten carbide powder to the second tungsten carbide powder can be any specific value of 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, or any value in the range of 2-3:1. In the present invention, the average particle size of the cobalt powder is 14-15 μm. It can be understood that the average particle size can be any specific value among 14.1 μm, 14.2 μm, 14.3 μm, 14.4 μm, 14.5 μm, 14.6 μm, 14.7 μm, 14.8 μm, 14.9 μm, 15 μm or any value within the range of 14-15 μm.

[0038] In the present invention, in step (1), the ball milling is carried out in an argon or nitrogen protective atmosphere, the rotation speed of the ball mill is 150-200 r / min, the ball-to-material ratio is 8-10:1, and the ball milling time is 24-36 h. In the present invention, the rotation speed of the ball mill can be any specific value of 150 r / min, 160 r / min, 170 r / min, 180 r / min, 190 r / min, 200 r / min, or any value within the range of 150-200 r / min. In the present invention, the ball-to-material ratio refers to the mass ratio of the grinding body to the material in the ball mill, and the ball-to-material ratio can be any specific value of 8:1, 9:1, 10:1, or any value within the range of 8-10:1. The ball milling time can be any specific value of 24h, 25h, 26h, 27h, 28h, 29h, 30h, 31h, 32h, 33h, 34h, 35h, 36h or any value within the range of 24-36h.

[0039] In the present invention, in step (2), the mixed slurry is vacuum dried and sieved to obtain tungsten carbide-cobalt powder. In the present invention, the vacuum drying temperature is 90-100°C. It can be understood that the temperature can be any specific value of 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C, 100°C or any value within the range of 90-100°C.

[0040] In the present invention, in step (3), the tungsten carbide-cobalt powder is placed in a mold and subjected to compression molding to obtain a green compact. In the present invention, in step (3), the pressure of the compression molding is 100-300 MPa. It is understood that the pressure can be any specific value of 100 MPa, 120 MPa, 140 MPa, 160 MPa, 180 MPa, 200 MPa, 220 MPa, 240 MPa, 260 MPa, 280 MPa, 300 MPa or any value within the range of 100-300 MPa.

[0041] In the present invention, in step (4), the compact is placed in a vacuum sintering furnace for primary sintering, secondary sintering and tertiary sintering in sequence, and the sintered blank is naturally cooled to room temperature to obtain a high-toughness wear-resistant tungsten carbide alloy. In the present invention, the vacuum degree in the vacuum sintering furnace is kept less than 0.1 Pa during the sintering process. In the present invention, the temperature of the primary sintering is 400-450°C. It can be understood that the temperature can be any specific value of 400°C, 410°C, 420°C, 430°C, 440°C, 450°C or any value within the range of 400-450°C; the time of the primary sintering is 1-1.5h. It can be understood that the time can be any specific value of 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h or any value within the range of 1-1.5h. Preferably, the temperature of the primary sintering is 420-450°C, and the time of the primary sintering is 1-1.5h.

[0042] In the present invention, in step (4), the temperature of the secondary sintering is 900-950°C. It is understood that the temperature can be any specific value of 900°C, 910°C, 920°C, 930°C, 940°C, 950°C or any value within the range of 900-950°C; the time of the secondary sintering is 2-2.5h. It is understood that the time can be any specific value of 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h or any value within the range of 2-2.5h. Preferably, the temperature of the secondary sintering is 930-950°C, and the time of the secondary sintering is 2-2.5h.

[0043] In the present invention, in step (4), the temperature of the three sinterings is 1000-1100°C. It is understood that the temperature can be any specific value of 1000°C, 1010°C, 1020°C, 1030°C, 1040°C, 1050°C, 1060°C, 1070°C, 1080°C, 1090°C, 1100°C or any value within the range of 1000-1100°C; the time of the three sinterings is 1.5-2h. It is understood that the time can be any specific value of 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h or any value within the range of 1.5-2h. Preferably, the temperature of the three sinterings is 1050-1100°C, and the time of the three sinterings is 1.5-2h.

[0044] According to another aspect of the present invention, there is also provided a high-toughness wear-resistant tungsten carbide alloy prepared according to the above preparation method.

[0045] In the present invention, the tungsten carbide alloy includes 80% tungsten carbide and 20% cobalt by mass percentage. In the present invention, the density of the tungsten carbide alloy is 13.4-13.8g / cm³, and it is understood that its density can be any specific value of 13.4g / cm³, 13.5g / cm³, 13.6g / cm³, 13.7g / cm³, 13.8g / cm³, or any value within the range of 13.4-13.8g / cm³; the average particle size of the tungsten carbide grains is 1.4-1.8μm, and it is understood that its average particle size can be any specific value of 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, or any value within the range of 1.4-1.8μm.

[0046] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0047] The chemical additives used in the examples and comparative examples of the present invention are all commercially available, and their specific information is as follows:

[0048] Tungsten carbide powder: purity greater than 99.9%, purchased from Xiamen Jinlu Special Alloy Co., Ltd.; cobalt powder: purity greater than 99.9%, purchased from Bohuas Nano Technology (Ningbo) Co., Ltd.; anhydrous ethanol: purchased from Aladdin Reagent Co., Ltd.

[0049] Example 1

[0050] The method for preparing a high-toughness wear-resistant tungsten carbide alloy described in this embodiment comprises the following steps:

[0051] (1) Add 1.5 kg of a first tungsten carbide powder with an average particle size of 0.85 μm, 0.5 kg of a second tungsten carbide powder with an average particle size of 1 μm, and 0.5 kg of a metal cobalt powder with an average particle size of 14 μm into a ball mill, add 20 kg of an alloy grinding rod, add 2 L of anhydrous ethanol, and ball mill for 24 h in an argon protective atmosphere at a speed of 150 r / min to obtain a mixed slurry;

[0052] (2) vacuum drying the mixed slurry at 100° C. for 10 h, and sieving to obtain tungsten carbide-cobalt powder;

[0053] (3) placing the tungsten carbide-cobalt powder in a mold and performing compression molding at 300 MPa to obtain a compact;

[0054] (4) The pressed green sheet is placed in a vacuum sintering furnace and sintered at 450°C for 1 h, 950°C for 2.5 h, and 1100°C for 2 h. During the sintering process, the vacuum degree in the vacuum sintering furnace is maintained at less than 0.1 Pa. The sintered green sheet is naturally cooled to room temperature to obtain a high-toughness, wear-resistant tungsten carbide alloy.

[0055] Example 2

[0056] The method for preparing a high-toughness wear-resistant tungsten carbide alloy described in this embodiment comprises the following steps:

[0057] (1) Add 1.5 kg of a first tungsten carbide powder with an average particle size of 0.95 μm, 0.5 kg of a second tungsten carbide powder with an average particle size of 1.5 μm, and 0.5 kg of a metal cobalt powder with an average particle size of 15 μm into a ball mill, add 25 kg of an alloy grinding rod, add 3 L of anhydrous ethanol, and ball mill for 36 hours in a nitrogen protective atmosphere at a speed of 200 r / min to obtain a mixed slurry;

[0058] (2) drying the mixed slurry under vacuum at 90° C. for 12 h, and sieving to obtain tungsten carbide-cobalt powder;

[0059] (3) placing the tungsten carbide-cobalt powder in a mold and performing compression molding at 100 MPa to obtain a compact;

[0060] (4) The pressed green sheet is placed in a vacuum sintering furnace and sintered at 400°C for 1.5 h, 900°C for 2 h, and 1000°C for 1.5 h. During the sintering process, the vacuum degree in the vacuum sintering furnace is maintained at less than 0.1 Pa. The sintered green sheet is naturally cooled to room temperature to obtain a high-toughness and wear-resistant tungsten carbide alloy.

[0061] Example 3

[0062] The method for preparing a high-toughness wear-resistant tungsten carbide alloy described in this embodiment comprises the following steps:

[0063] (1) Add 2 kg of the first tungsten carbide powder with an average particle size of 0.85 μm, 1 kg of the second tungsten carbide powder with an average particle size of 1 μm, and 0.75 kg of the metal cobalt powder with an average particle size of 14 μm into a ball mill, add 30 kg of alloy grinding rods, add 3 L of anhydrous ethanol, and ball mill for 24 hours in an argon protective atmosphere at a speed of 180 r / min to obtain a mixed slurry;

[0064] (2) vacuum drying the mixed slurry at 100° C. for 10 h, and sieving to obtain tungsten carbide-cobalt powder;

[0065] (3) placing the tungsten carbide-cobalt powder in a mold and performing compression molding at 200 MPa to obtain a compact;

[0066] (4) The pressed green sheet is placed in a vacuum sintering furnace and sintered at 420°C for 1.2 h, 930°C for 2.2 h, and 1050°C for 2 h. During the sintering process, the vacuum degree in the vacuum sintering furnace is maintained at less than 0.1 Pa. The sintered green sheet is naturally cooled to room temperature to obtain a high-toughness and wear-resistant tungsten carbide alloy.

[0067] Comparative Example 1

[0068] The preparation method of the tungsten carbide alloy described in this comparative example is the same as that of Example 1, except that the sintering in step (4) is a secondary sintering. The specific sintering process is: placing the pressed green sheet in a vacuum sintering furnace and sintering it at 450°C for 2h and at 950°C for 3.5h. During the sintering process, the vacuum degree in the vacuum sintering furnace is maintained at less than 0.1Pa. The sintered green sheet is naturally cooled to room temperature to obtain the tungsten carbide alloy.

[0069] Comparative Example 2

[0070] The preparation method of the tungsten carbide alloy described in this comparative example is the same as that of Example 1, except that the sintering temperature in step (4) is different. The specific sintering process is: placing the pressed green sheet in a vacuum sintering furnace and sintering it at 350°C for 1 hour, 850°C for 2.5 hours and 950°C for 2 hours. During the sintering process, the vacuum degree in the vacuum sintering furnace is maintained at less than 0.1 Pa. The sintered green sheet is naturally cooled to room temperature to obtain the tungsten carbide alloy.

[0071] Comparative Example 3

[0072] The preparation method of the tungsten carbide alloy described in this comparative example is the same as that of Example 1, except that in step (1), 1.5 kg of the first tungsten carbide powder with an average particle size of 0.85 μm and 0.5 kg of the second tungsten carbide powder with an average particle size of 1 μm are replaced with 2.5 kg of the first tungsten carbide powder with an average particle size of 0.85 μm.

[0073] Performance Testing

[0074] The tungsten carbide alloys described in Examples 1-3 and Comparative Examples 1-3 were tested for performance according to the following method. The specific results are shown in Table 1.

[0075] (1) Density: Tested in accordance with standard GB / T3850-2015, measuring at least 3 different locations and taking the average value.

[0076] (2) Hardness: Test in accordance with standard GB / T3849.1-2015, measure at least 5 different positions and take the average value.

[0077] (3) Average grain size: Tested in accordance with standard GB / T3488.2-2018 / ISO4499-2:2008 "Metallographic determination of cemented carbide microstructure Part 2: Measurement of WC grain size".

[0078] (4) Flexural strength: tested according to standard GB / T6569-2006, specimen size 3 mm × 4 mm × 36 mm, loading rate 0.5 mm / min.

[0079] (5) Impact toughness: tested in accordance with standard GB / T1817-2017.

[0080] (6) Service life: The tungsten carbide alloys in the embodiments of the present invention and the comparative examples were used to make molds, and the normal service life of the molds was recorded.

[0081] Table 1 Performance data of tungsten carbide alloys described in Examples 1-3 and Comparative Examples 1-3

[0082] .

[0083] It can be seen from Table 1 that the density and hardness of the tungsten carbide alloys described in Examples 1-3 of the present invention are large, the grain size is small, the bending strength and impact toughness are high, and the service life of the mold is long, indicating that the wear resistance is good. It can be seen from Example 1 and Comparative Examples 1-2 that the sintering method changes during the preparation of the tungsten carbide alloys in Comparative Examples 1-2, the grain size of the obtained tungsten carbide alloy becomes larger, and the bending strength, impact toughness and service life all decrease, indicating that the wear resistance and toughness of the material decrease. It can be seen from Example 1 and Comparative Example 3 that the tungsten carbide powder of a single particle size is used as the raw material for preparing the tungsten carbide alloy in Comparative Example 3, and the bending strength, impact toughness and service life of the obtained tungsten carbide alloy all decrease, indicating that the wear resistance and toughness of the material decrease.

[0084] Figure 1 is the metallographic structure diagram of the tungsten carbide alloy in Example 1 (1500×), Figure 2 This is the metallographic structure diagram (1500×) of the tungsten carbide alloy in comparative example 3. Figure 1-2 It can be seen that the phase structure of the tungsten carbide alloy in Example 1 of the present invention is uniformly distributed, the average size of the tungsten carbide grains is small, and the grain distribution is relatively uniform and tight. The microstructure can significantly improve the wear resistance and toughness of the alloy material; the tungsten carbide alloy in Comparative Example 3 has a larger grain size and uneven distribution, and the tungsten carbide grain distribution is relatively loose, thereby reducing the wear resistance and toughness of the alloy material in Comparative Example 3.

[0085] It can be seen that the present invention improves the microstructure of the prepared tungsten carbide alloy by controlling the process conditions of the tungsten carbide alloy preparation process, especially the control of the three sintering temperatures and times, and the average size of the tungsten carbide grains is small, and the particle size distribution is relatively uniform, thereby significantly improving the wear resistance and toughness of the tungsten carbide alloy. In addition, the sintering method described in the present invention improves the fluidity of cobalt, so that cobalt can be evenly distributed around tungsten carbide, while also reducing the presence of pores, which is conducive to improving the density of the material. In addition, by selecting two tungsten carbide powders of specific particle sizes for compounding, the two synergistically improve the microstructure of the tungsten carbide alloy, making the grain size of the tungsten carbide alloy more uniform and the porosity lower, thereby significantly improving the wear resistance and toughness of the tungsten carbide alloy.

[0086] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a high-toughness wear-resistant tungsten carbide alloy, characterized in that: The steps include: (1) Add tungsten carbide powder and metal cobalt powder into a ball mill, add anhydrous ethanol, and perform ball milling to obtain a mixed slurry; (2) vacuum drying the mixed slurry and sieving it to obtain tungsten carbide-cobalt powder; (3) placing the tungsten carbide-cobalt powder in a mold and performing compression molding to obtain a compact; (4) Placing the compact in a vacuum sintering furnace for primary sintering, secondary sintering and tertiary sintering in sequence, and cooling the sintered compact to room temperature naturally to obtain a high-toughness wear-resistant tungsten carbide alloy; the primary sintering temperature is 400-450°C, and the primary sintering time is 1-1.5h; the secondary sintering temperature is 900-950°C, and the secondary sintering time is 2-2.5h; the tertiary sintering temperature is 1000-1100°C, and the tertiary sintering time is 1.5-2h; during the sintering process, the vacuum degree in the vacuum sintering furnace is maintained at less than 0.1Pa; In step (1), the tungsten carbide powder is a mixture of a first tungsten carbide powder with an average particle size of 0.85-0.95 μm and a second tungsten carbide powder with an average particle size of 1-1.5 μm, and the mass ratio of the first tungsten carbide powder to the second tungsten carbide powder is 2-3:1; the average particle size of the cobalt powder is 14-15 μm; in step (3), the pressure of the compression molding is 100-300 MPa.

2. The method for preparing the high-toughness wear-resistant tungsten carbide alloy according to claim 1, characterized in that: In step (1), the ball milling is carried out in an argon or nitrogen protective atmosphere, the rotation speed of the ball mill is 150-200 r / min, the ball-to-material ratio is 8-10:1, and the ball milling time is 24-36 h.

3. A high-toughness wear-resistant tungsten carbide alloy, characterized in that: The alloy is prepared according to the preparation method according to any one of claims 1-2.

4. The high-toughness wear-resistant tungsten carbide alloy according to claim 3, characterized in that: The tungsten carbide alloy comprises, by mass percentage, 80% tungsten carbide and 20% cobalt.

5. The high-toughness wear-resistant tungsten carbide alloy according to claim 3, characterized in that: The density of the tungsten carbide alloy is 13.4-13.8 g / cm³, and the average particle size of the tungsten carbide grains is 1.4-1.8 μm.

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