An erosion-resistant cemented carbide substrate and its manufacture, a polycrystalline diamond composite, a drill bit, a cutting tool and a drill bit

Abstract

This invention provides an erosion-resistant cemented carbide matrix and its fabrication, a polycrystalline diamond composite material, drill teeth, cutting tools, and drill bits. The erosion-resistant cemented carbide matrix comprises an inner layer, an intermediate transition layer, and an outer layer. The inner layer, by weight, contains 80-94% tungsten carbide and 6-20% cobalt. The intermediate transition layer, by weight, contains 80-94% tungsten carbide, 3-10% cobalt, 1-3% nickel, 1-3% chromium, and 1-4% molybdenum. The outer layer, by weight, contains 80-90% tungsten carbide, 3-8% cobalt, 1-2% nickel, 1-2% chromium, 1-2% molybdenum, 2-3% zirconium, and 2-3% niobium. The erosion-resistant cemented carbide matrix provided by this invention possesses high strength as well as significant resistance to electrochemical corrosion and erosion, making it suitable for many extreme environments.

Description

Technical Field

[0001] This invention relates to an erosion-resistant cemented carbide matrix and its fabrication, polycrystalline diamond composite materials, drill teeth, cutting tools and drill bits, belonging to the field of materials science and engineering technology, particularly the field of polycrystalline diamond composite materials technology. Background Technology

[0002] In modern industry, polycrystalline diamond composites (PDC) are widely used in many technical fields such as oil and gas extraction and mineral processing due to their excellent hardness and wear resistance. Currently, the matrix of these PDC-based cutting tools or drills is mainly composed of tungsten carbide (WC) and cobalt (Co), i.e., tungsten carbide-cobalt alloys. Utilizing their excellent physical and mechanical properties, they exhibit good overall performance in complex and harsh working environments. However, with the increase in mining depth and the complexity of geological conditions, traditional WC-Co matrices face a series of challenges, especially the electrochemical corrosion problems encountered when operating in high-temperature, high-pressure water-based drilling fluid environments.

[0003] In the high-temperature, high-pressure environment of water-based drilling fluids, the matrix material of drill bits is often subjected to electrochemical corrosion. This corrosion phenomenon usually originates from the reaction between the matrix and the acidic operating environment, causing the gradual loss of cobalt from the matrix. This leads to a decrease in the structural integrity of the drill bit, resulting in a significant reduction in the strength and toughness of the matrix. This not only shortens the service life of the drill bit but also affects cutting efficiency and increases production costs. Therefore, improving the resistance to electrochemical corrosion of polycrystalline diamond composite drill bit matrix while ensuring its strength has become an urgent need in the current oil and gas drilling industry.

[0004] Therefore, providing a novel erosion-resistant cemented carbide matrix and its fabrication, as well as polycrystalline diamond composite materials, drill teeth, cutting tools, and drill bits have become urgent technical problems to be solved in this field. Summary of the Invention

[0005] To address the aforementioned shortcomings and deficiencies, the present invention aims to provide an erosion-resistant cemented carbide matrix and its fabrication, a polycrystalline diamond composite material, drill teeth, cutting tools, and drill bits. The invention aims to improve the overall performance of drill teeth in high-temperature, high-pressure water-based drilling fluid environments (i.e., electrochemical corrosion environments) by improving the composition, structural design (and employing different components and proportions in each layer) and process flow of the cemented carbide matrix material. This will enhance the overall performance of the drill teeth and meet the high-efficiency operation requirements of modern oil and gas drilling.

[0006] To achieve the above objectives, in one aspect, the present invention provides an erosion-resistant cemented carbide substrate, wherein the erosion-resistant cemented carbide substrate comprises an inner layer, an intermediate transition layer, and an outer layer; wherein, based on 100% of the total weight of the inner layer, it contains 80-94% tungsten carbide and 6-20% cobalt, and the sum of the total content of all components in the inner layer is 100%; based on 100% of the total weight of the intermediate transition layer, it contains 80-94% tungsten carbide and 6-20% cobalt. The intermediate transition layer contains tungsten carbide, 3-10% cobalt, 1-3% nickel, 1-3% chromium, and 1-4% molybdenum, with the total content of each component in the intermediate transition layer being 100%. The outer layer, by weight 100%, contains 80-90% tungsten carbide, 3-8% cobalt, 1-2% nickel, 1-2% chromium, 1-2% molybdenum, 2-3% zirconium, and 2-3% niobium, with the total content of each component in the outer layer being 100%.

[0007] In a specific embodiment of the erosion-resistant cemented carbide substrate described above, the thickness of the inner layer accounts for 40-70% of the total thickness of the erosion-resistant cemented carbide substrate, the thickness of the intermediate transition layer accounts for 20-40% of the total thickness of the erosion-resistant cemented carbide substrate, and the thickness of the outer layer accounts for 10-25% of the total thickness of the erosion-resistant cemented carbide substrate, and the sum of the percentages of the inner layer, the intermediate transition layer, and the outer layer in the total thickness of the erosion-resistant cemented carbide substrate is 100%.

[0008] The introduction of nickel, chromium, and molybdenum into the erosion-resistant cemented carbide matrix of this invention improves its strength and toughness in the face of erosion and wear, reducing the risk of failure of the matrix material under extreme conditions. The introduction of zirconium and niobium alleviates the electrochemical corrosion suffered by the matrix material in acidic operating environments under high temperature and pressure, reducing the frequency of maintenance and replacement, and thus lowering the overall operating cost. In other words, this invention significantly improves the durability of the matrix material and the finished products made from it in acidic, high-temperature, and high-pressure environments, effectively resisting electrochemical corrosion and extending service life. Furthermore, the material composition of the erosion-resistant cemented carbide matrix can be flexibly adjusted according to different operating conditions to meet the cutting requirements of various oil, gas, and mineral mining operations, thereby improving cutting efficiency.

[0009] On the other hand, the present invention also provides a method for manufacturing an erosion-resistant cemented carbide substrate, wherein the erosion-resistant cemented carbide substrate is the erosion-resistant cemented carbide substrate described above, and the manufacturing method includes:

[0010] Step (1): Weigh out tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder and niobium powder;

[0011] Step (2): Based on the composition and ratio of the inner layer, intermediate transition layer and outer layer of the erosion-resistant cemented carbide substrate, the raw material components corresponding to the inner layer, intermediate transition layer and outer layer are fully mixed, and the mixed powder is subjected to hydrogen reduction treatment. Then, the powders after hydrogen reduction treatment are stacked layer by layer in the order of inner, middle and outer and cold-pressed to obtain the pre-pressed product.

[0012] Step (3): Sinter the pre-pressed product to obtain the sintered product;

[0013] Step (4): Post-process the sintered product to obtain an erosion-resistant cemented carbide matrix.

[0014] As a specific embodiment of the manufacturing method described above in this invention, in step (1), tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder and niobium powder are all high-purity products, and their purity is not less than 99.99%.

[0015] As a specific embodiment of the manufacturing method described above in this invention, in step (1), the particle size of the tungsten carbide is 3±0.5μm, the particle size of the cobalt powder, nickel powder, chromium powder and molybdenum powder is 1±0.15μm, and the particle size of the zirconium powder and niobium powder is 0.5±0.1μm.

[0016] As a specific embodiment of the manufacturing method described above in this invention, in step (2), the thorough mixing can be achieved by ball milling to reduce the adhesion between particles and improve the mixing effect.

[0017] In one specific embodiment of the manufacturing method described above, in step (2), the temperature of the hydrogen reduction treatment is 600-1200℃, and the holding time is 0.5-2h. The hydrogen reduction treatment can remove impurities from the particles / powder. In some embodiments of the present invention, the heating and cooling rates during the hydrogen reduction treatment can both be 20℃ / min.

[0018] As a specific embodiment of the manufacturing method described above in this invention, in step (2), the pressure of cold pressing is 10-200 MPa to ensure the density and shape accuracy of the matrix material.

[0019] As a specific embodiment of the manufacturing method described above in this invention, in step (3), the sintering temperature is 1100-1600℃, the pressure is 3-10GPa, and the holding time is 5-20min, so as to ensure that a strong bond is formed between tungsten carbide and the metal matrix and to improve the density and strength of the matrix material.

[0020] In some embodiments of the present invention, the heating and cooling rates during the sintering process can both be 100°C / min. In some embodiments of the present invention, the pre-pressed product / green body is placed in a domestically produced hinged six-sided top press for high-temperature and high-pressure sintering.

[0021] As a specific embodiment of the manufacturing method described above in this invention, step (4) involves post-processing the sintered product, including: simultaneously heat-treating the sintered product and performing a surface sandblasting process. The heat treatment temperature is 300-800℃, the sandblasting medium for the surface sandblasting process is alumina, the sandblasting flow rate is 5-15 m / s, and the sandblasting angle is 30-90°. Heat treatment can release residual stress in the matrix material, while surface sandblasting can eliminate defects on the surface of the matrix material, further improving the matrix material's resistance to electrochemical corrosion and erosion. In summary, this post-processing can improve the microstructure of the matrix material, thereby optimizing the overall performance of the matrix material and the finished product made from it.

[0022] In another aspect, the present invention also provides a polycrystalline diamond composite material, wherein the polycrystalline diamond composite material comprises an erosion-resistant cemented carbide matrix and a polycrystalline diamond layer disposed on the surface of the matrix.

[0023] Wherein, the erosion-resistant cemented carbide substrate is the erosion-resistant cemented carbide substrate described above, or the erosion-resistant cemented carbide substrate is an erosion-resistant cemented carbide substrate prepared by the above-described method for preparing the erosion-resistant cemented carbide substrate.

[0024] In another aspect, the present invention also provides a drill bit, wherein the material of the drill bit is the polycrystalline diamond composite material described above.

[0025] In another aspect, the present invention also provides a cutting tool, wherein the material of the cutting tool is the polycrystalline diamond composite material described above.

[0026] In another aspect, the present invention also provides a drill bit, including a drill bit body and drill teeth, wherein the drill bit body and drill teeth are connected as one piece, and the drill teeth are the drill teeth described above.

[0027] Finally, the present invention also provides an application of a drill bit or cutting tool in processes requiring high hardness and wear resistance, such as oil drilling, natural gas drilling, or mineral mining operations, wherein the drill bit is the drill bit described above, or the cutting tool is the cutting tool described above.

[0028] The technical solution of the present invention has at least the following beneficial effects:

[0029] This invention introduces multiple metallic components—cobalt (Co), nickel (Ni), chromium (Cr), molybdenum (Mo), zirconium (Zr), and niobium (Nb)—into a cemented carbide matrix material, ensuring excellent density, strength, and stability. Simultaneously, the matrix structure is improved by employing a gradient structure design, dividing the cemented carbide matrix into three layers: inner, middle, and outer. The inner layer utilizes a high-cobalt-content tungsten carbide matrix to provide excellent toughness and impact resistance. The intermediate transition layer replaces some of the cobalt binder phase with nickel, chromium, and molybdenum. Through a gradient change in the proportions of cobalt, nickel, chromium, and molybdenum, the difference in thermal expansion between the inner and outer layers is mitigated, reducing interfacial stress concentration. Outer layer: High-melting-point, corrosion-resistant zirconium and niobium are added to the intermediate transition layer. Because nickel, chromium, molybdenum, zirconium and niobium in the outer layer have high melting points, high stability and do not react chemically with acids, the wear resistance of the outer layer of the matrix can be greatly improved as well as its resistance to electrochemical corrosion and erosion in high-temperature and high-pressure water-based drilling fluid environments.

[0030] In this invention, "gradient" refers to the gradual change in composition and functional properties from the inner to the outer layers of the erosion-resistant cemented carbide matrix material. This change is not abrupt, but rather a continuous and gradual transition between different layers achieved through the control of component ratios. This design allows the erosion-resistant cemented carbide matrix material to achieve a balance between load-bearing capacity, toughness, and surface wear resistance.

[0031] In summary, the "gradient" in this invention is mainly reflected in the fact that the erosion-resistant cemented carbide matrix is ​​sequentially composed of an inner layer, an intermediate transition layer, and an outer layer from the inside out. Furthermore, the types and proportions of alloying elements in the inner, intermediate, and outer layers change from simple to complex, resulting in a gradual optimization of performance from the inside out. Through this gradient change in composition and properties, the erosion-resistant cemented carbide matrix material possesses both core strength and toughness, as well as surface wear resistance and corrosion resistance, making it a functionalized gradient material.

[0032] In fabricating this cemented carbide matrix material, a powder layer-by-layer stacking method is employed. Powder metallurgy and high-temperature, high-pressure sintering technology are used to bond tungsten carbide with metal powder, effectively improving the density of the matrix material and inhibiting grain growth. This ensures the matrix material possesses high compactness (i.e., high density) and strength, achieving a strong bond between the polycrystalline diamond layer and the matrix, further enhancing oil and gas drilling efficiency, service life, and economic benefits. The design of this cemented carbide matrix material aims to enhance the electrochemical corrosion resistance and erosion resistance of drill bits or cutting tools under extreme working conditions such as oil and gas extraction and mineral processing. This improves their service performance under various complex working conditions, especially in the extreme operating environment of high-temperature, high-pressure acidic water-based drilling fluids, effectively extending tool life and increasing work efficiency.

[0033] In summary, the erosion-resistant cemented carbide matrix provided by this invention combines the wear-resistant and corrosion-resistant properties of tungsten carbide and stainless steel. While ensuring the strength of the matrix, it also gives it significant resistance to electrochemical corrosion and erosion. It is suitable for many extreme environments, including the service environment of high-temperature and high-pressure water-based drilling fluids. Furthermore, in these extreme environments, the matrix material still has excellent durability and a long service life. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 The image shows a comparison of the minimum number of impacts required for the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention and the cemented carbide substrates provided in Comparative Examples 1-7 to undergo impact resistance tests at an angle of 15° and a constant energy of 50J, recording the results.

[0036] Figure 2 Comparison of weight loss of the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention and the cemented carbide substrates provided in Comparative Examples 1-7 after corrosion at a constant temperature of 50°C for 100 hours in an environment with a pH of 4.5. Detailed Implementation

[0037] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0038] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0039] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0040] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0041] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0042] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0044] Example 1

[0045] This embodiment provides an erosion-resistant cemented carbide substrate, which is prepared by a method including the following specific steps:

[0046] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%; Zirconium powder: particle size 0.5μm, purity 99.99%; Niobium powder: particle size 0.5μm, purity 99.99%.

[0047] Step (2): A gradient structure design is adopted, dividing the substrate into 3 layers from the inside out. The inner layer (the thickness of the inner layer in the finished erosion-resistant cemented carbide substrate is 4 mm) has the following composition by mass percentage: tungsten carbide 87%, cobalt 13%; the intermediate transition layer (the thickness of the intermediate transition layer in the finished erosion-resistant cemented carbide substrate is 3 mm) has the following composition by mass percentage: tungsten carbide 87%, cobalt 7%, nickel 2%, chromium 2%, molybdenum 2%; and the outer layer (the thickness of the outer layer in the finished erosion-resistant cemented carbide substrate is 2 mm) has the following composition by mass percentage: tungsten carbide 87%, cobalt 5%, nickel 1%, chromium 1%, molybdenum 1%, zirconium 2.5%, niobium 2.5%.

[0048] For the raw materials corresponding to the inner layer, intermediate transition layer and outer layer, a ball mill was used to mix them for 12 hours. The completely mixed initial powder was then subjected to hydrogen reduction treatment, specifically, it was kept at 900℃ for 1 hour, and the heating and cooling rates were both 20℃ / min.

[0049] Take out the pre-treated powder, stack the treated component powders layer by layer in the manner of inner, middle and outer layers, and pre-press them in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0050] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0051] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, so as to obtain an erosion-resistant hard alloy matrix.

[0052] Comparative Example 1

[0053] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0054] Step (1): Obtain tungsten carbide and cobalt powder according to the following parameters: tungsten carbide powder: particle size 3μm, purity 99.99%; cobalt powder: particle size 1μm, purity 99.99%.

[0055] Step (2): Gradient structure design is not adopted, wherein the mass percentage of each component of the matrix is: tungsten carbide 87% and cobalt 13%;

[0056] The powder was mixed in a ball mill for 12 hours, and then the completely mixed initial powder was subjected to hydrogen reduction treatment, specifically by holding it at 900℃ for 1 hour, with both the heating and cooling rates being 20℃ / min.

[0057] The pre-treated powder is taken out, the treated powder is stacked into layers, and pre-pressed in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0058] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0059] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0060] Comparative Example 2

[0061] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0062] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%; Zirconium powder: particle size 0.5μm, purity 99.99%; Niobium powder: particle size 0.5μm, purity 99.99%.

[0063] Step (2): Gradient structure design is not adopted. The mass percentage of each component in the matrix is ​​as follows: tungsten carbide 87%, cobalt 5%, nickel 1%, chromium 1%, molybdenum 1%, zirconium 2.5%, niobium 2.5%.

[0064] The initial powder was mixed in a ball mill for 12 hours and then subjected to hydrogen reduction treatment, specifically by holding it at 900℃ for 1 hour, with both the heating and cooling rates being 20℃ / min.

[0065] The pre-treated powder is taken out, the treated powder is stacked into layers, and pre-pressed in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0066] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0067] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0068] Comparative Example 3

[0069] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0070] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%.

[0071] Step (2): Gradient structure design is not adopted. The mass percentage of each component in the matrix is: tungsten carbide 87%, cobalt 7%, nickel 2%, chromium 2%, molybdenum 2%.

[0072] The initial powder was mixed in a ball mill for 12 hours and then subjected to hydrogen reduction treatment, specifically by holding it at 900℃ for 1 hour, with both the heating and cooling rates being 20℃ / min.

[0073] The pre-treated powder is taken out, the treated powder is stacked into layers, and pre-pressed in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0074] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0075] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0076] Comparative Example 4

[0077] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0078] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%.

[0079] Step (2): A partial gradient structure design is adopted, dividing the substrate into two layers from the inside out, with only an inner layer and an intermediate transition layer, and no outer layer. The inner layer (4mm thick in the finished cemented carbide substrate) has the following composition by mass percentage: tungsten carbide 87%, cobalt 13%; the intermediate transition layer (3mm thick in the finished cemented carbide substrate) has the following composition by mass percentage: tungsten carbide 87%, cobalt 7%, nickel 2%, chromium 2%, molybdenum 2%.

[0080] For the raw materials corresponding to the inner layer and the intermediate transition layer, a ball mill was used to mix them for 12 hours. The completely mixed initial powder was then subjected to hydrogen reduction treatment, specifically by holding at 900℃ for 1 hour, with both the heating and cooling rates being 20℃ / min.

[0081] Take out the pre-treated powder, stack the treated component powders layer by layer in an inner and middle manner, and pre-press them in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0082] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0083] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0084] Comparative Example 5

[0085] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0086] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%; Zirconium powder: particle size 0.5μm, purity 99.99%; Niobium powder: particle size 0.5μm, purity 99.99%.

[0087] Step (2): A partial gradient structure design is adopted, dividing the substrate into two layers from the inside out, with only an inner layer and an outer layer, and no intermediate transition layer. The inner layer (4mm thick in the finished cemented carbide substrate) has the following composition by mass percentage: tungsten carbide 87%, cobalt 13%; the outer layer (2mm thick in the finished cemented carbide substrate) has the following composition by mass percentage: tungsten carbide 87%, cobalt 5%, nickel 1%, chromium 1%, molybdenum 1%, zirconium 2.5%, niobium 2.5%.

[0088] For the raw materials corresponding to the inner and outer layers, a ball mill was used to mix them for 12 hours. The completely mixed initial powder was then subjected to hydrogen reduction treatment, specifically by holding it at 900℃ for 1 hour, with both the heating and cooling rates being 20℃ / min.

[0089] Take out the pre-treated powder, stack the treated component powders layer by layer in an inner and outer manner, and pre-press them in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0090] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0091] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0092] Comparative Example 6

[0093] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0094] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%; Zirconium powder: particle size 0.5μm, purity 99.99%; Niobium powder: particle size 0.5μm, purity 99.99%.

[0095] Step (2): A gradient structure design is partially adopted, dividing the substrate into two layers from the inside out, with only an intermediate transition layer and an outer layer, and no inner layer. The intermediate transition layer (3mm thick in the finished cemented carbide substrate) has the following composition by mass percentage: tungsten carbide 87%, cobalt 7%, nickel 2%, chromium 2%, molybdenum 2%; the outer layer (2mm thick in the finished intermediate transition layer) has the following composition by mass percentage: tungsten carbide 87%, cobalt 5%, nickel 1%, chromium 1%, molybdenum 1%, zirconium 2.5%, niobium 2.5%.

[0096] For the raw materials corresponding to the intermediate transition layer and the outer layer, a ball mill was used to mix them for 12 hours. The completely mixed initial powder was then subjected to hydrogen reduction treatment, specifically by holding at 900℃ for 1 hour, with both the heating and cooling rates being 20℃ / min.

[0097] Take out the pre-treated powder, stack the treated component powders layer by layer in the middle and outer layers, and pre-press them in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0098] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0099] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0100] Comparative Example 7

[0101] This comparative example provides a cemented carbide substrate, which is prepared by a method including the following specific steps:

[0102] Step (1): Obtain tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder, and niobium powder according to the following parameters: Tungsten carbide powder: particle size 3μm, purity 99.99%; Cobalt powder: particle size 1μm, purity 99.99%; Nickel powder: particle size 1μm, purity 99.99%; Chromium powder: particle size 1μm, purity 99.99%; Molybdenum powder: particle size 1μm, purity 99.99%; Zirconium powder: particle size 0.5μm, purity 99.99%; Niobium powder: particle size 0.5μm, purity 99.99%.

[0103] Step (2): A gradient structure design is adopted, dividing the substrate into 3 layers from the inside out. The inner layer (the thickness of the inner layer in the finished cemented carbide substrate is 4mm) has the following composition by mass: tungsten carbide 87%, cobalt 13%; the intermediate transition layer (the thickness of the intermediate transition layer in the finished cemented carbide substrate is 3mm) has the following composition by mass: tungsten carbide 87%, cobalt 7%, nickel 2%, chromium 2%, molybdenum 2%; and the outer layer (the thickness of the outer layer in the finished cemented carbide substrate is 2mm) has the following composition by mass: tungsten carbide 90%, cobalt 5%, nickel 1%, chromium 1%, molybdenum 1%, zirconium 1%, niobium 1%.

[0104] For the raw materials corresponding to the inner layer, intermediate transition layer and outer layer, a ball mill was used to mix them for 12 hours. The completely mixed initial powder was then subjected to hydrogen reduction treatment, specifically, it was kept at 900℃ for 1 hour, and the heating and cooling rates were both 20℃ / min.

[0105] Take out the pre-treated powder, stack the treated component powders layer by layer in the manner of inner, middle and outer layers, and pre-press them in a mold under a pressure of 20MPa to obtain a pre-pressed blank.

[0106] Step (3): Assemble the pre-pressed blank into a composite block, and then place the composite block in a domestic hinged six-sided press. First, pressurize it to 5GPa, then heat it to 1400℃, and hold it at 5GPa / 1400℃ for 5 minutes for sintering. Then, cool it down and then depressurize it to end the experiment. The heating and cooling rates are both 100℃ / min.

[0107] Step (4): Finally, the synthesis equipment returns to the original state and the sintered sample block is taken out from the synthesis block. The sintered sample is first heat-treated at 500℃ to release the residual stress in the matrix. At the same time, it is then subjected to a sandblasting process. The sandblasting medium is alumina, the sandblasting flow rate is 5m / s, and the sandblasting angle is 90° to further improve its resistance to electrochemical corrosion and erosion, thus obtaining a cemented carbide matrix.

[0108] Test Example 1

[0109] This test example subjected the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention and the cemented carbide substrates provided in Comparative Examples 1-7 to impact tests at an angle of 15° and a constant energy of 50J. During the impact tests, the minimum number of impacts required for each substrate to undergo significant fracture was recorded. This minimum number of impacts was used as a characterization method for the strength of the cemented carbide substrate, thereby simulating the impact conditions experienced by the PDC substrate during drilling. The comparison chart of the minimum number of impacts obtained in this test example is shown below. Figure 1 As shown.

[0110] from Figure 1 As can be seen, the erosion-resistant cemented carbide substrate provided in Example 1 of this invention requires a minimum of 60 impacts to cause significant breakage during the impact resistance test, while the cemented carbide substrate provided in Comparative Example 1 requires a minimum of 33 impacts to cause significant breakage during the impact resistance test. The cemented carbide substrates provided in Comparative Examples 2, 3, 4, 5, 6, and 7 require a minimum of 41, 37, 44, 47, 50, and 54 impacts to cause significant breakage during the impact resistance test, respectively. Therefore, compared to the cemented carbide substrates provided in Comparative Examples 1-7, the erosion-resistant cemented carbide substrate provided in Example 1 of this invention requires the highest minimum number of impacts to cause significant breakage during the impact resistance test, indicating that it has the best impact resistance and the highest strength.

[0111] Specifically, comparing the minimum number of impacts required for significant fracture of the erosion-resistant cemented carbide substrates in Comparative Examples 1 and 3 shows that replacing the cobalt portion in the substrate with nickel, chromium, and molybdenum effectively improves the substrate's strength. Comparing the minimum number of impacts required for significant fracture of the erosion-resistant cemented carbide substrates in Comparative Examples 2 and 3 shows that, in addition to replacing the cobalt portion in the substrate with nickel, chromium, and molybdenum, further adding zirconium and niobium, which have high elastic modulus and high stability, further effectively improves the substrate's strength. Comparing the minimum number of impacts required for significant fracture of the erosion-resistant cemented carbide substrate provided in Example 1 of this invention and the cemented carbide substrate provided in Comparative Example 2 shows that, compared to a single structure, the erosion-resistant cemented carbide substrate obtained by the gradient structure design in Example 1 of this invention exhibits significantly improved strength. By comparing the minimum number of impacts required for the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention to undergo significant fracture with the cemented carbide substrates provided in Comparative Examples 4, 5, and 6, it can be seen that, compared with cemented carbide substrates with a partially gradient structure, the three-layer gradient structure design of Example 1 of the present invention can significantly improve the strength of the substrate. By comparing the minimum number of impacts required for the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention to undergo significant fracture with the cemented carbide substrate provided in Comparative Example 7, it can be seen that, based on the same three-layer gradient structure, the zirconium and niobium content in the outer layer of the erosion-resistant cemented carbide substrate of Example 1 of the present invention is within the range specified in this application, and its strength is superior to that of the cemented carbide substrate provided in Comparative Example 1, whose zirconium and niobium content in the outer layer is not within the range specified in this application.

[0112] Test Example 2

[0113] This test example examines the weight loss of the erosion-resistant cemented carbide substrate provided in Example 1 of this invention and the cemented carbide substrates provided in Comparative Examples 1-7 under constant temperature corrosion at 50°C for 100 hours in an environment with a pH of 4.5. Weight loss is used as a characterization method for electrochemical corrosion resistance, thereby simulating the electrochemical corrosion experienced by the PDC substrate during drilling. The weight loss comparison chart obtained in this test example is shown below. Figure 2 As shown.

[0114] from Figure 2As can be seen, the erosion-resistant cemented carbide substrate provided in Example 1 of this invention lost 35 mg of weight during the test, with a weight loss rate of 0.35 mg / h. In contrast, the cemented carbide substrate provided in Comparative Example 1 lost as much as 110 mg of weight during the test, with a weight loss rate of 1.1 mg / h. The cemented carbide substrates provided in Comparative Examples 2, 3, 4, 5, 6, and 7 lost 39 mg, 80 mg, 76 mg, 62 mg, 56 mg, and 50 mg of weight, respectively, with weight loss rates of 0.39 mg / h, 0.80 mg / h, 0.76 mg / h, 0.62 mg / h, 0.56 mg / h, and 0.50 mg / h, respectively. Therefore, the erosion-resistant cemented carbide substrate provided in Example 1 of this invention has a lower weight loss rate than the cemented carbide substrates provided in Comparative Examples 1-7, indicating that it has superior resistance to electrochemical corrosion.

[0115] Specifically, comparing the weight loss and weight loss rate of the cemented carbide substrates in Comparative Examples 1 and 3 shows that replacing the cobalt portion in the substrate with nickel, chromium, and molybdenum effectively improves the substrate's resistance to electrochemical corrosion. Comparing the weight loss and weight loss rate of the cemented carbide substrates in Comparative Examples 2 and 3 shows that, in addition to replacing the cobalt portion in the substrate with nickel, chromium, and molybdenum, the addition of corrosion-resistant zirconium and niobium further effectively improves the substrate's resistance to electrochemical corrosion. Comparing the weight loss and weight loss rate of the erosion-resistant cemented carbide substrate provided in Example 1 of this invention and the cemented carbide substrate provided in Comparative Example 2 shows that, compared to a single structure, the erosion-resistant cemented carbide substrate with a gradient structure design in Example 1 of this invention exhibits superior resistance to electrochemical corrosion. By comparing the weight loss and weight loss rate of the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention with those of Comparative Examples 4, 5, and 6, it can be seen that the erosion-resistant cemented carbide substrate with a three-layer gradient structure design in Example 1 of the present invention exhibits superior electrochemical corrosion resistance compared to cemented carbide substrates with a partially gradient structure. By comparing the weight loss and weight loss rate of the erosion-resistant cemented carbide substrate provided in Example 1 of the present invention with those of Comparative Example 7, it can be seen that, based on the same three-layer gradient structure, the zirconium and niobium content in the outer layer of the erosion-resistant cemented carbide substrate of Example 1 of the present invention, within the range specified in this invention, exhibits significantly better electrochemical corrosion resistance than the cemented carbide substrate provided in Comparative Example 1, where the zirconium and niobium content in the outer layer is not within the range specified in this invention.

[0116] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. An erosion-resistant hard alloy matrix, characterized in that, The erosion-resistant cemented carbide matrix comprises an inner layer, an intermediate transition layer, and an outer layer; wherein, based on the total weight of the inner layer (100%), it contains 80-94% tungsten carbide and 6-20% cobalt; based on the total weight of the intermediate transition layer (100%), it contains 80-94% tungsten carbide, 3-10% cobalt, 1-3% nickel, 1-3% chromium, and 1-4% molybdenum; and based on the total weight of the outer layer (100%), it contains 80-90% tungsten carbide, 3-8% cobalt, 1-2% nickel, 1-2% chromium, 1-2% molybdenum, 2-3% zirconium, and 2-3% niobium.

2. The erosion-resistant cemented carbide matrix according to claim 1, characterized in that, The thickness of the inner layer accounts for 40-70% of the total thickness of the erosion-resistant cemented carbide substrate, the thickness of the intermediate transition layer accounts for 20-40% of the total thickness of the erosion-resistant cemented carbide substrate, and the thickness of the outer layer accounts for 10-25% of the total thickness of the erosion-resistant cemented carbide substrate.

3. A method for fabricating an erosion-resistant hard alloy substrate, characterized in that, The erosion-resistant cemented carbide substrate is the erosion-resistant cemented carbide substrate as described in claim 1 or 2, and its manufacturing method includes: Step (1): Weigh out tungsten carbide, cobalt powder, nickel powder, chromium powder, molybdenum powder, zirconium powder and niobium powder; Step (2): Based on the composition and ratio of the inner layer, intermediate transition layer and outer layer of the erosion-resistant cemented carbide substrate, the raw material components corresponding to the inner layer, intermediate transition layer and outer layer are fully mixed, and the mixed powder is subjected to hydrogen reduction treatment. Then, the powders after hydrogen reduction treatment are stacked layer by layer in the order of inner, middle and outer and cold-pressed to obtain the pre-pressed product. Step (3): Sinter the pre-pressed product to obtain the sintered product; Step (4): Post-process the sintered product to obtain an erosion-resistant cemented carbide matrix.

4. The manufacturing method according to claim 3, characterized in that, In step (1), the particle size of tungsten carbide is 3±0.5μm, the particle size of cobalt powder, nickel powder, chromium powder and molybdenum powder is 1±0.15μm, and the particle size of zirconium powder and niobium powder is 0.5±0.1μm.

5. The manufacturing method according to claim 3 or 4, characterized in that, In step (2), the temperature of the hydrogen reduction treatment is 600-1200℃, and the holding time is 0.5-2h.

6. The manufacturing method according to claim 3 or 4, characterized in that, In step (2), the pressure of cold pressing is 10-200 MPa.

7. The manufacturing method according to claim 3 or 4, characterized in that, In step (3), the sintering temperature is 1100-1600℃, the pressure is 3-10GPa, and the holding time is 5-20min.

8. The manufacturing method according to claim 3 or 4, characterized in that, In step (4), the sintered product is post-processed, including: the sintered product is heat-treated and then subjected to surface sandblasting, wherein the temperature of the heat treatment is 300-800℃, the sandblasting medium of the surface sandblasting process is alumina, the sandblasting flow rate is 5-15m / s, and the sandblasting angle is 30-90°.

9. A polycrystalline diamond composite material, characterized in that, The polycrystalline diamond composite material comprises an erosion-resistant cemented carbide matrix and a polycrystalline diamond layer disposed on the surface of the matrix, wherein the erosion-resistant cemented carbide matrix is ​​the erosion-resistant cemented carbide matrix as described in claim 1 or 2, or the erosion-resistant cemented carbide matrix is ​​an erosion-resistant cemented carbide matrix prepared by the method for preparing the erosion-resistant cemented carbide matrix as described in any one of claims 3-8.

10. A drill tooth, characterized in that, The drill bit is made of the polycrystalline diamond composite material as described in claim 9.

11. A cutting tool, characterized in that, The material of the cutting tool is the polycrystalline diamond composite material as described in claim 9.

12. A drill bit, comprising a drill bit body and drill teeth, wherein the drill bit body and drill teeth are integrally connected, characterized in that, The drill bit is the drill bit as described in claim 10.

13. The application of a drill bit or cutting tool in oil drilling, natural gas drilling, or mineral mining operations, characterized in that, The drill bit is the drill bit of claim 12, or the cutting tool is the cutting tool of claim 11.

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