A hard alloy for mine exploitation screw drill and a preparation method thereof

Abstract

The application belongs to the technical field of hard alloy and particularly relates to a hard alloy for mine exploitation screw thread drilling and a preparation method thereof, the preparation method comprising the following steps: S1, obtaining tungsten carbide, cobalt powder, tantalum carbide and nickel powder as raw materials, wherein the tungsten carbide is composed of first tungsten carbide and second tungsten carbide; S2, after the cobalt powder, the tantalum carbide and the first tungsten carbide are mixed and then subjected to first wet grinding, first mixed material is obtained, after the first mixed material and the nickel powder are mixed and then subjected to second wet grinding, second mixed material is obtained, after the second mixed material and the second tungsten carbide are mixed and then subjected to third wet grinding, third mixed material is obtained; S3, after the third mixed material is subjected to drying, pressing and sintering, the hard alloy is obtained. According to the application, the large ball material ratio and the coarser tungsten carbide can effectively break the agglomeration of tantalum carbide powder and improve the dispersibility of the tantalum carbide powder, nickel is additionally added as a second phase toughening agent, a large-diameter grinding rod and a small-diameter grinding ball are adopted to improve the grinding efficiency and promote the homogeneous distribution of the additive and the binder and improve the toughness of the product.

Description

Technical Field

[0001] This application belongs to the field of cemented carbide technology, specifically relating to a cemented carbide for use in threaded drills for mining and its preparation method. Background Technology

[0002] Tungsten carbide-cobalt (WC-Co) cemented carbide is an alloy material made by powder metallurgy (batching, mixing, pressing, and high-temperature sintering) with tungsten carbide (WC) as the hard phase and metallic cobalt (Co) as the binder phase. Its core characteristic lies in the "hardness-toughness balance"—it possesses extremely high hardness (86-93 HRA, far exceeding that of high-speed steel) and excellent wear resistance, resisting wear from metal cutting and rock grinding. It also boasts good bending strength (1500-4000 MPa) and certain impact toughness due to the binding effect of the cobalt phase, capable of withstanding loads under medium to low impact conditions. Furthermore, it exhibits excellent high-temperature resistance (maintaining high hardness at 800-1000℃) and chemical stability, making it resistant to chemical reactions with metal workpieces or rocks. In the mining and infrastructure sectors, it is used to manufacture rock drill bits, tunnel boring machine tools, and crusher teeth for drilling and crushing hard rocks such as granite and limestone, serving as a key basic material supporting high-end manufacturing and resource development.

[0003] Carbide thread drills for rock drilling rigs primarily utilize tungsten-cobalt carbide, with hardness (HRA≥90) and bending strength (≥3200MPa) enhanced through high-temperature, high-pressure sintering. Thread types include international standard wave threads (R22, R25, R28, etc.) and trapezoidal threads (T38, T45, etc.), with the R32 specification widely used in hydraulic rock drilling rigs. The design incorporates a two-stage core structure, variable helical chip removal grooves, and double-helical internal cooling holes, significantly improving chip removal efficiency and vibration resistance. However, current models lack sufficient toughness in high-impact rock environments, making them prone to chipping or breakage. Therefore, developing high-toughness carbide drills while ensuring wear resistance is crucial in mining operations. Summary of the Invention

[0004] To solve the above-mentioned technical problems, this application provides a method for preparing cemented carbide for threaded drills in mining, comprising the following steps: S1, obtaining tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials, wherein the tungsten carbide is composed of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 3.6-4.0µm, and the particle size of the second tungsten carbide is 3.0-3.4µm; S2, mixing the cobalt powder, the tantalum carbide, and the first tungsten carbide and performing a first wet milling to obtain a first mixture, mixing the first mixture and the nickel powder and performing a second wet milling to obtain a second mixture, mixing the second mixture and the second tungsten carbide and performing a third wet milling to obtain a third mixture, wherein the grinding media for the first wet milling, the second wet milling, and the third wet milling are grinding rods and grinding balls; S3, drying, pressing, and sintering the third mixture to obtain cemented carbide.

[0005] As a preferred embodiment of the method for preparing cemented carbide for threaded drills in mining as described in this application, in step S1, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials, by mass percentage, are 92.5%-94.9%, 4.0%-6.8%, 0.1%-0.5%, and 0.2%-1.0%, respectively. The mass ratio of the first tungsten carbide to the second tungsten carbide is (10-20):(90-80), and the particle size of the cobalt powder is 1.0-1.5µm. Alcohol is also obtained simultaneously with the raw materials, and the liquid-to-solid ratio of the alcohol to the raw materials is (300-350) mL:1kg. The alcohol is divided into first alcohol and second alcohol, and the volume ratio of the first alcohol to the second alcohol is (20-30):(80-70).

[0006] As a preferred embodiment of the method for preparing a cemented carbide for threaded drills in mining as described in this application, step S2 further includes: adding the first alcohol during the first wet grinding process, wherein the first wet grinding time is 1-3 hours.

[0007] As a preferred embodiment of the method for preparing cemented carbide for threaded drills in mining as described in this application, in step S2, the second wet grinding time is 1-2 hours.

[0008] As a preferred embodiment of the method for preparing a cemented carbide for threaded drills in mining as described in this application, step S2 further includes: adding the second alcohol and paraffin during the third wet grinding process, wherein the third wet grinding time is 30-40 hours.

[0009] As a preferred embodiment of the method for preparing cemented carbide for threaded drills in mining as described in this application, in step S2, the mass of the grinding media is 3-6 times the mass of the raw material, the mass ratio of the grinding rod to the grinding ball is (80-90):(20-10), the size of the grinding rod is Φ(11-13)×16mm, and the size of the grinding ball is Φ5-7mm.

[0010] As a preferred embodiment of the method for preparing a cemented carbide for threaded drills in mining as described in this application, the drying method in step S3 is spray drying.

[0011] As a preferred embodiment of the method for preparing cemented carbide for threaded drills in mining as described in this application, in step S3, the sintering temperature is 1420-1460℃ and the sintering time is 1-2h.

[0012] This application also provides a cemented carbide for use in mining thread drills, which is prepared using the above-described method for preparing cemented carbide for use in mining thread drills.

[0013] As a preferred embodiment of the cemented carbide used in mining thread drills described in this application, the cemented carbide has a hardness ≥1510HV10 and a fracture toughness ≥13.2MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount of the cemented carbide was ≤0.04cm. 3 .

[0014] The beneficial effects of this application are as follows:

[0015] This application provides a cemented carbide for use in threaded drills in mining and its preparation method. The cemented carbide prepared by this method exhibits high wear resistance and toughness. The addition of tantalum carbide improves the high-temperature stability and interfacial properties of the hard phase, simultaneously increasing alloy hardness and inhibiting abnormal grain growth while maintaining toughness. Adding nickel as a second phase enhances the alloy's fracture toughness and corrosion resistance. Polygonal and equiaxed tungsten carbide grains are beneficial for improving product toughness, while the presence of triangular tungsten carbide grains significantly reduces toughness. This application utilizes a large ball-to-particle ratio and coarser tungsten carbide particles to pre-grind tantalum carbide powder, effectively breaking up tantalum carbide powder agglomeration and improving its dispersibility, thus promoting uniform distribution of tantalum carbide in the alloy. After pre-grinding, the tungsten carbide particle size in the resulting alloy is similar in performance to that prepared with finer tungsten carbide, without affecting the overall alloy performance. This application uses a large-diameter grinding rod and a small-diameter grinding ball to improve grinding efficiency and promote the homogeneous distribution of additives and binders, thereby improving product toughness. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 Metallographic images of the cemented carbide prepared in Example 1 of this application;

[0018] Figure 2 Metallographic images of the cemented carbide prepared in Example 2 of this application;

[0019] Figure 3 Metallographic images of the cemented carbide prepared in Example 3 of this application;

[0020] Figure 4 Metallographic images of the cemented carbide prepared in Example 4 of this application;

[0021] Figure 5 Metallographic images of the cemented carbide prepared in Comparative Example 1 of this application;

[0022] Figure 6 Metallographic images of the cemented carbide prepared in Comparative Example 2 of this application;

[0023] Figure 7 Metallographic images of the cemented carbide prepared in Comparative Example 3 of this application;

[0024] Figure 8 Metallographic images of the cemented carbide prepared in Comparative Example 5 of this application;

[0025] Figure 9 Metallographic images of the cemented carbide prepared in Comparative Example 7 of this application.

[0026] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] This application provides a method for preparing cemented carbide for threaded drills in mining, comprising the following steps:

[0029] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. The tungsten carbide is composed of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 3.6-4.0µm, and the particle size of the second tungsten carbide is 3.0-3.4µm.

[0030] By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 92.5%-94.9%, 4.0%-6.8%, 0.1%-0.5%, and 0.2%-1.0%, respectively. The mass ratio of the first tungsten carbide to the second tungsten carbide is (10-20):(90-80), and the particle size of the cobalt powder is 1.0-1.5µm. Alcohol is also obtained simultaneously with the raw materials. The liquid-to-solid ratio of the alcohol to the raw materials is (300-350) mL:1kg. The alcohol is divided into first alcohol and second alcohol, and the volume ratio of the first alcohol to the second alcohol is (20-30):(80-70).

[0031] Specifically, the mass ratio of the first tungsten carbide to the second tungsten carbide is any one or any two of 10:90, 11:89, 12:88, 13:87, 14:86, 15:85, 16:84, 17:83, 18:82, 19:81, and 20:80; the liquid-solid ratio of the alcohol to the raw material is any one or any two of 300 mL / kg, 310 mL / kg, 320 mL / kg, 330 mL / kg, 340 mL / kg, and 350 mL / kg; and the volume ratio of the first alcohol to the second alcohol is any one or any two of 20:80, 21:79, 22:78, 23:77, 24:76, 25:75, 26:74, 27:73, 28:72, 29:71, and 30:70.

[0032] S2. The cobalt powder, tantalum carbide and the first tungsten carbide are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture and the nickel powder are mixed and then subjected to a second wet milling to obtain a second mixture. The second mixture and the second tungsten carbide are mixed and then subjected to a third wet milling to obtain a third mixture. The grinding media for the first wet milling, the second wet milling and the third wet milling are grinding rods and grinding balls.

[0033] The first alcohol is added during the first wet milling process, and the first wet milling time is 1-3 hours; the second wet milling time is 1-2 hours; the second alcohol and paraffin are added during the third wet milling process, and the third wet milling time is 30-40 hours; the mass of the grinding media is 3-6 times the mass of the raw material, the mass ratio of the grinding rod to the grinding ball is (80-90):(20-10), the size of the grinding rod is Φ(11-13)×16mm, and the size of the grinding ball is Φ5-7mm;

[0034] Specifically, the mass of the grinding media is any one or any two of 3, 4, 5, and 6 times the mass of the raw material.

[0035] S3. The third mixture is dried, pressed and sintered to obtain a cemented carbide.

[0036] The drying method is spray drying; the sintering temperature is 1420-1460℃, and the sintering time is 1-2 hours;

[0037] Specifically, the sintering temperature is any one or a range between 1420℃, 1430℃, 1440℃, 1450℃, and 1460℃, and the sintering time is any one or a range between 1.0h, 1.2h, 1.4h, 1.6h, 1.8h, and 2.0h.

[0038] The technical solution of this application will be further described below with reference to specific embodiments.

[0039] Example 1

[0040] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0041] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.0µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 94.9%, 4.0%, 0.1%, and 1.0%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The cobalt powder has a particle size of 1.0µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 300mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0042] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 1 hour, the second wet milling time is 1 hour, and the third wet milling time is 30 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 6 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ13×16mm, and the size of the grinding balls is Φ7mm.

[0043] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1420℃ and the sintering time is 2h.

[0044] Please see Figure 1 , Figure 1 The image shows a metallographic image of the cemented carbide prepared in Example 1 of this application. It can be seen that the tungsten carbide particles in the cemented carbide prepared in Example 1 exhibit a bicrystalline morphology, with the larger particles being polygonal or equiaxed. The cemented carbide has a hardness of 1550 HV10 and a fracture toughness of 13.21 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0343 cm. 3 .

[0045] Example 2

[0046] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0047] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 3.8µm and the particle size of the second tungsten carbide is 3.2µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.6%, 5.5%, 0.3%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 15:85. The cobalt powder has a particle size of 1.2µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 25:75.

[0048] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 35 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 85:15. The size of the grinding rods is Φ12×16mm, and the size of the grinding balls is Φ6mm.

[0049] S3. The third mixture is spray-dried, pressed and sintered to obtain cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1.5h.

[0050] Please see Figure 2 , Figure 2 The image shows a metallographic image of the cemented carbide prepared in Example 2 of this application. It can be seen that the tungsten carbide particles in the cemented carbide prepared in Example 2 exhibit a bicrystalline morphology, with the larger particles being polygonal or equiaxed. The cemented carbide has a hardness of 1531 HV10 and a fracture toughness of 13.43 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0365 cm. 3 .

[0051] Example 3

[0052] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0053] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 3.6µm and the particle size of the second tungsten carbide is 3.4µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 92.5%, 6.8%, 0.5%, and 0.2%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 10:90. The cobalt powder has a particle size of 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 350mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 20:80.

[0054] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 3 hours, the second wet milling time is 2 hours, and the third wet milling time is 40 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 3 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 90:10. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0055] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1460℃ and the sintering time is 1h.

[0056] Please see Figure 3 , Figure 3 The image shows a metallographic image of the cemented carbide prepared in Example 3 of this application. It can be seen that the tungsten carbide particles in the cemented carbide prepared in Example 3 exhibit a bicrystalline morphology, with the larger particles being polygonal or equiaxed. The cemented carbide has a hardness of 1519 HV10 and a fracture toughness of 13.64 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0386 cm. 3 .

[0057] Example 4

[0058] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0059] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.7%, 5.4%, 0.3%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The cobalt powder has a particle size of 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0060] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0061] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0062] Please see Figure 4 , Figure 4 The image shows a metallographic image of the cemented carbide prepared in Example 4 of this application. It can be seen that the tungsten carbide particles in the cemented carbide prepared in Example 4 exhibit a twinned morphology, with the larger particles being polygonal or equiaxed. The cemented carbide has a hardness of 1510 HV10 and a fracture toughness of 13.95 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0395 cm. 3 .

[0063] Comparative Example 1

[0064] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0065] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials, and simultaneously obtain alcohol. The particle size of tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.7%, 5.4%, 0.3%, and 0.6%, respectively. The particle size of cobalt powder is 1.5µm. The mass of the raw materials is 1kg, and the volume of alcohol is 330mL. The alcohol is divided into primary alcohol and secondary alcohol, and the volume ratio of primary alcohol to secondary alcohol is 30:70.

[0066] S2. Cobalt powder, tantalum carbide, and a first type of alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is then mixed with nickel powder and subjected to a second wet milling to obtain a second mixture. The second mixture, tungsten carbide, a second type of alcohol, and paraffin wax are then mixed and subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0067] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0068] Please see Figure 5 , Figure 5 The image shows a metallographic image of the cemented carbide prepared in Comparative Example 1 of this application. It can be seen that the cemented carbide prepared in Comparative Example 1 contains triangular tungsten carbide particles. The hardness of the cemented carbide is 1508 HV10, and the fracture toughness is 12.81 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.041 cm. 3 .

[0069] Comparative Example 2

[0070] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0071] S1. Obtain tungsten carbide, cobalt powder, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, and nickel powder in the raw materials are 94%, 5.4%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The particle size of the cobalt powder is 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0072] S2. Cobalt powder, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0073] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0074] Please see Figure 6 , Figure 6 The image shows a metallographic image of the cemented carbide prepared in Comparative Example 2 of this application. It can be seen that the cemented carbide prepared in Comparative Example 2 contains multiple triangular tungsten carbide particles. The hardness of the cemented carbide is 1443 HV10, and its fracture toughness is 16.33 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.055 cm. 3 .

[0075] Comparative Example 3

[0076] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0077] S1. Obtain tungsten carbide, cobalt powder, and tantalum carbide as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, and tantalum carbide in the raw materials are 93.7%, 6%, and 0.3%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The particle size of the cobalt powder is 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0078] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture, second tungsten carbide, second alcohol, and paraffin are mixed and then subjected to a second wet milling to obtain a second mixture. The first wet milling time is 2 hours, and the second wet milling time is 36 hours. The grinding media for the first and second wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0079] S3. The second mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0080] Please see Figure 7 , Figure 7 The image shows a metallographic image of the cemented carbide prepared in Comparative Example 3 of this application. It can be seen that the cemented carbide prepared in Comparative Example 3 contains abnormally large particles. The hardness of the cemented carbide is 1495 HV10, and the fracture toughness is 12.31 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0427 cm. 3 .

[0081] Comparative Example 4

[0082] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0083] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.7%, 5.4%, 0.3%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The cobalt powder has a particle size of 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0084] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is then mixed with nickel powder and subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are then mixed and subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second, and third wet milling is a grinding rod. The mass of the grinding media is 4 times the mass of the raw materials, and the size of the grinding rod is Φ11×16mm.

[0085] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0086] The cemented carbide prepared in Comparative Example 4 showed no abnormally large particles, had a hardness of 1489 HV10, and a fracture toughness of 12.75 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0434 cm. 3 .

[0087] Comparative Example 5

[0088] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0089] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 6.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.7%, 5.4%, 0.3%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The cobalt powder has a particle size of 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0090] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0091] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0092] Please see Figure 8 , Figure 8 The image shows a metallographic image of the cemented carbide prepared in Comparative Example 5 of this application. It can be seen that the tungsten carbide particles in the cemented carbide prepared in Comparative Example 5 exhibit a bicrystalline morphology, containing multiple triangular tungsten carbide particles and coarse-grained aggregates. The hardness of the cemented carbide is 1460 HV10, and its fracture toughness is 12.22 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0488 cm. 3 .

[0093] Comparative Example 6

[0094] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0095] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.7%, 5.4%, 0.3%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The cobalt powder has a particle size of 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 60:40.

[0096] S2. Cobalt powder, tantalum carbide, first tungsten carbide, and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture is mixed with nickel powder and then subjected to a second wet milling to obtain a second mixture. The second mixture, second tungsten carbide, second alcohol, and paraffin wax are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second, and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rods is Φ11×16mm, and the size of the grinding balls is Φ5mm.

[0097] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0098] The cemented carbide prepared in Comparative Example 6 showed no abnormally large particles, had a hardness of 1502 HV10, and a fracture toughness of 12.98 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0423 cm. 3 .

[0099] Comparative Example 7

[0100] A method for preparing cemented carbide for threaded drills in mining, the specific steps of which are as follows:

[0101] S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. Simultaneously, obtain ethanol. The tungsten carbide consists of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 4.0µm and the particle size of the second tungsten carbide is 3.3µm. By mass percentage, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials are 93.7%, 5.4%, 0.3%, and 0.6%, respectively, with a mass ratio of first tungsten carbide to second tungsten carbide of 20:80. The cobalt powder has a particle size of 1.5µm. The mass of the raw materials is 1kg, and the volume of the ethanol is 330mL. The ethanol is divided into first ethanol and second ethanol, with a volume ratio of first ethanol to second ethanol of 30:70.

[0102] S2. Cobalt powder and first alcohol are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture and nickel powder are mixed and then subjected to a second wet milling to obtain a second mixture. The second mixture, first tungsten carbide, second tungsten carbide, tantalum carbide, second alcohol and paraffin are mixed and then subjected to a third wet milling to obtain a third mixture. The first wet milling time is 2 hours, the second wet milling time is 1.5 hours, and the third wet milling time is 36 hours. The grinding media for the first, second and third wet milling are grinding rods and grinding balls. The mass of the grinding media is 4 times the mass of the raw materials. The mass ratio of grinding rods to grinding balls is 80:20. The size of the grinding rod is Φ11×16mm, and the size of the grinding ball is Φ5mm.

[0103] S3. The third mixture is spray-dried, pressed and sintered to obtain a cemented carbide; the sintering temperature is 1440℃ and the sintering time is 1h.

[0104] Please see Figure 9 , Figure 9 The image shows a metallographic image of the cemented carbide prepared in Comparative Example 7 of this application. It can be seen that the tantalum carbide in the cemented carbide prepared in Comparative Example 7 has poor dispersion and agglomeration. The hardness of the cemented carbide is 1493 HV10, and the fracture toughness is 12.85 MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount was 0.0431 cm. 3 .

[0105] As can be seen from the above examples and comparative examples: Example 4, combined with Comparative Example 1, shows that adding coarser-grained tungsten carbide and pre-grinding it together with additives can effectively break up the agglomeration of tantalum carbide powder, thereby improving its dispersibility and promoting the uniform distribution of tantalum carbide in the alloy, thus improving the wear resistance and toughness of the cemented carbide; Example 4, combined with Comparative Example 2, shows that adding tantalum carbide can improve the high-temperature stability and interface characteristics of the hard phase, improving the alloy hardness and inhibiting abnormal grain growth while maintaining toughness; Example 4, combined with Comparative Example 3, shows that adding nickel as a second phase for toughening can improve the fracture toughness and corrosion resistance of the alloy; Example 4, combined with Comparative Example 4, shows that a large-diameter grinding rod plus a small-diameter grinding ball can improve grinding efficiency and promote the homogeneous distribution of additives and binders, thereby improving the toughness of the alloy; Example 4, combined with Comparative Example 5, shows that controlling the particle size of the pre-ground tungsten carbide within a certain range can effectively avoid... The absence of triangular tungsten carbide grains and coarse-grained agglomeration in the alloy results in tungsten carbide grains with properties similar to those of alloys prepared with finer tungsten carbide. This method improves the dispersibility of additives while maintaining the tungsten carbide grain size, thus enhancing the wear resistance and toughness of the alloy. Example 4, combined with Comparative Example 6, demonstrates that controlling the solid-liquid ratio within a suitable range during the pre-grinding process effectively improves the dispersion of the additives, thereby enhancing the wear resistance and toughness of the alloy. Example 4, combined with Comparative Example 7, shows that the lack of pre-grinding of tantalum carbide leads to poor dispersibility and agglomeration, failing to improve the wear resistance and toughness of the alloy. Combining Examples 1-4 and Comparative Examples 1-7, it is evident that the method for preparing a cemented carbide for mining thread drills in this application can improve toughness while ensuring the wear resistance of the cemented carbide, thereby reducing wear and increasing service life.

[0106] This application provides a cemented carbide for use in threaded drills in mining and its preparation method. The cemented carbide prepared by this method has high wear resistance and toughness. This application pre-grinds tantalum carbide and coarser tungsten carbide together. The large ball-to-material ratio and the coarser tungsten carbide particles can effectively break up the agglomeration of tantalum carbide powder, thereby improving its dispersibility and promoting the uniform distribution of tantalum carbide in the alloy. After pre-grinding, the tungsten carbide particle size in the alloy prepared by the coarser tungsten carbide is similar to that of the alloy prepared by the finer tungsten carbide particles, without affecting its overall alloy performance. This application also adds nickel as a second phase to toughen and improve the fracture toughness of the alloy. It also uses a large-diameter grinding rod with a small-diameter grinding ball to improve grinding efficiency and promote the homogeneous distribution of additives and binders, thereby improving the toughness of the product.

[0107] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for preparing cemented carbide for threaded drills in mining, characterized in that, Includes the following steps: S1. Obtain tungsten carbide, cobalt powder, tantalum carbide, and nickel powder as raw materials. The tungsten carbide is composed of first tungsten carbide and second tungsten carbide, wherein the particle size of the first tungsten carbide is 3.6-4.0µm, and the particle size of the second tungsten carbide is 3.0-3.4µm. S2. The cobalt powder, tantalum carbide and the first tungsten carbide are mixed and then subjected to a first wet milling to obtain a first mixture. The first mixture and the nickel powder are mixed and then subjected to a second wet milling to obtain a second mixture. The second mixture and the second tungsten carbide are mixed and then subjected to a third wet milling to obtain a third mixture. The grinding media for the first wet milling, the second wet milling and the third wet milling are grinding rods and grinding balls. S3. The third mixture is dried, pressed and sintered to obtain a cemented carbide.

2. The method for preparing a cemented carbide for threaded drills in mining according to claim 1, characterized in that, In step S1, the proportions of tungsten carbide, cobalt powder, tantalum carbide, and nickel powder in the raw materials, by mass percentage, are 92.5%-94.9%, 4.0%-6.8%, 0.1%-0.5%, and 0.2%-1.0%, respectively. The mass ratio of the first tungsten carbide to the second tungsten carbide is (10-20):(90-80), and the particle size of the cobalt powder is 1.0-1.5µm. Alcohol is also obtained simultaneously with the raw materials. The liquid-to-solid ratio of the alcohol to the raw materials is (300-350) mL:1kg. The alcohol is divided into first alcohol and second alcohol, and the volume ratio of the first alcohol to the second alcohol is (20-30):(80-70).

3. The method for preparing a cemented carbide for threaded drills in mining according to claim 2, characterized in that, Step S2 further includes: adding the first alcohol during the first wet milling process, wherein the first wet milling time is 1-3 hours.

4. The method for preparing a cemented carbide for threaded drills in mining according to claim 1, characterized in that, In step S2, the second wet milling time is 1-2 hours.

5. The method for preparing a cemented carbide for threaded drills in mining according to claim 2, characterized in that, Step S2 further includes adding the second alcohol and paraffin during the third wet milling process, wherein the third wet milling time is 30-40 hours.

6. The method for preparing a cemented carbide for threaded drills in mining according to claim 1, characterized in that, In step S2, the mass of the grinding medium is 3-6 times the mass of the raw material, the mass ratio of the grinding rod to the grinding ball is (80-90):(20-10), the size of the grinding rod is Φ(11-13)×16mm, and the size of the grinding ball is Φ5-7mm.

7. The method for preparing a cemented carbide for threaded drills in mining according to claim 1, characterized in that, In step S3, the drying method is spray drying.

8. The method for preparing a cemented carbide for threaded drills in mining according to claim 1, characterized in that, In step S3, the sintering temperature is 1420-1460℃, and the sintering time is 1-2 hours.

9. A cemented carbide for use in mining thread drills, characterized in that, It is prepared by the method for preparing a cemented carbide for threaded drills in mining as described in any one of claims 1-8.

10. A cemented carbide for use in mining thread drills according to claim 9, characterized in that, The hardness of the cemented carbide is ≥1510HV10, and the fracture toughness of the cemented carbide is ≥13.2MPa·m. 1 / 2 The cemented carbide was tested using the method specified in GB / T34501-2017, and the wear amount of the cemented carbide was ≤0.04cm. 3 .

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