A non-homogeneous structure impregnated diamond bit and a method of manufacturing the same

Abstract

The application discloses a non-homogeneous structure impregnated diamond drill bit and a preparation method thereof. The non-homogeneous structure impregnated diamond drill bit comprises a non-homogeneous structure working layer, the non-homogeneous structure working layer is in a ring structure, a plurality of water gap areas are distributed in the circumferential direction of the whole ring structure, the non-homogeneous structure working layer is uniformly divided into a plurality of fan-shaped sections, and any one fan-shaped section comprises a boundary area and a middle area. The volume fraction of diamonds in the boundary area is greater than that in the middle area, and the any one fan-shaped section further comprises a plurality of blocks with different components or different particle sizes. The drill bit provided by the application is provided with diamond concentration to form multi-dimensional non-uniform changes. The differentiated wear can make the originally flat drill bit bottom lip surface naturally form a wavy or toothed profile. The area of the convex hard layer is small, and under the same drilling pressure, a very high local specific pressure can be obtained, so that the diamond can be more easily eaten into hard rock, and the mechanical drilling speed is greatly improved.

Description

Technical Field

[0001] This invention belongs to the fields of machining and drilling engineering, and particularly relates to a heterogeneous impregnated diamond drill bit and its preparation method. Background Technology

[0002] With the continuous progress and development of global society, the demand for energy resources is showing an increasingly intensified trend. Traditional shallow resource extraction can no longer meet the demand, forcing drilling to shift to deeper strata with more complex geological structures to explore new resources. In this process, the drill bit, as an indispensable core tool in drilling operations, directly affects drilling efficiency and service life, thus influencing the length of the entire drilling cycle and the drilling cost. Especially in the field of deep-hole drilling, due to the extremely high temperature and pressure environment and complex and variable geological conditions, selecting a high-efficiency and long-life drill bit is particularly important.

[0003] 3D printing technology, as a cutting-edge technology in the field of intelligent manufacturing, has attracted widespread attention and application in the manufacturing industry in recent years. This technology, with its high flexibility, precision, and customizability, has brought revolutionary changes to traditional manufacturing. Combining 3D printing technology with the production of diamond drill bits undoubtedly opens up a new path for the research and development of high-efficiency, long-life drill bits. Through 3D printing technology, diamond drill bits with complex geometries and optimized internal structures can be precisely designed and manufactured according to specific drilling needs and geological conditions, thereby significantly improving their drilling efficiency and service life. Existing diamond impregnated layered drill bits mostly employ radial soft-hard interlayering, primarily to cut concentric circular grooves at the bottom of the hole, utilizing the track effect of the grooves to prevent radial runout of the drill bit, focusing on stability and guidance to prevent deviation, and assisting in improving rock breaking efficiency. Designs for high drilling efficiency in diamond arrangement are relatively rare. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the first objective of this invention is to provide a heterogeneous impregnated diamond drill bit for drilling. The heterogeneous impregnated diamond drill bit provided by this invention features a diamond concentration that varies in a multi-dimensional, non-uniform manner, primarily circumferentially. This differential wear causes the originally flat bottom lip of the drill bit to naturally form a wavy or toothed profile. The protruding hard layer area is small, and under the same drilling pressure, extremely high local specific pressure can be obtained, making it easier for the diamond to penetrate hard rock. The alternating circumferential hard and soft layers will successively scrape across the rock at the bottom of the hole, inducing rock fatigue and significantly increasing the mechanical drilling speed.

[0005] The third objective of this invention is to provide a method for preparing a heterogeneous structure impregnated diamond drill bit. The preparation method provided by this invention can achieve non-uniform positioning and arrangement of diamonds, overcome the problem of difficult diamond positioning and arrangement in traditional manufacturing processes, and at the same time enable the production of drill bits with complex structures.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention discloses a heterogeneous structure impregnated diamond drill bit. The heterogeneous structure impregnated diamond drill bit includes a heterogeneous structure working layer, which is composed entirely of diamond and a metal matrix. The heterogeneous structure working layer has a ring-shaped structure with several sprue zones distributed circumferentially around the entire ring structure, uniformly dividing the heterogeneous structure working layer into multiple fan-shaped segments. Each fan-shaped segment includes a boundary region and a central region. The boundary region is disposed around the entire edge of the fan-shaped segment, wherein the volume fraction of diamond in the boundary region is greater than the volume fraction of diamond in the central region. Each fan-shaped segment also contains several blocks with different compositions or different particle sizes.

[0008] In this invention, by controlling the volume fraction of diamond in the heterogeneous working layer, the concentration of diamond in the impregnated block boundary region, i.e., the region near the inner and outer diameters or the nozzle, is higher than the volume fraction in the central region of the impregnated block, which is far from the inner and outer diameters. This allows the heterogeneous impregnated diamond drill bit to have both excellent wear resistance and cutting efficiency. The high diamond concentration near the inner and outer diameters and the nozzle provides better wear resistance, adapting to the fact that the inner and outer diameters of the drill bit directly contact the borehole wall, core, and flushing fluid during drilling, resulting in more intense friction and impact. The central part undertakes the cutting task and uses a lower concentration to achieve better cutting efficiency. In addition, the differentiated setting of blocks with different compositions or particle sizes will naturally form a wavy or toothed profile on the originally flat bottom lip surface of the drill bit, further improving the mechanical drilling speed.

[0009] In a preferred embodiment, the fan-shaped segment is provided with N annular component blocks in the radial direction. The annular component blocks include a first component block and a second component block. The first component block and the second component block are alternately nested in the radial direction, wherein the volume fraction of diamond in the first component block is greater than the volume fraction of diamond in the second component block and / or the particle size of diamond in the first component block is greater than the particle size of diamond in the second component block.

[0010] When the volume fraction of diamond in the first component block is greater than the volume fraction of diamond in the second component block, the volume fraction of diamond in the first component block is 60% to 80%, and the volume fraction of diamond in the second component block is 6% to 40%.

[0011] When the diamond particle size in the first component block is larger than that in the second component block, the diamond particle size in the first component block is 20~50 mesh, and the diamond particle size in the second component block is 60~100 mesh.

[0012] In a preferred embodiment, the fan-shaped segment is provided with M unit blocks along the circumferential direction. Each unit block includes a first component unit and a second component unit. The first component unit and the second component unit are alternately arranged along the circumferential direction, wherein the volume fraction of diamond in the first component unit is greater than the volume fraction of diamond in the first component unit and / or the particle size of diamond in the first component unit is greater than the particle size of diamond in the first component unit.

[0013] When the volume fraction of diamond in the first component unit is greater than the volume fraction of diamond in the second component unit, the volume fraction of diamond in the first component unit is 60% to 80%, and the volume fraction of diamond in the second component unit is 6% to 40%.

[0014] When the diamond particle size in the first component unit is larger than that in the second component unit, the diamond particle size in the first component unit is 20~50 mesh, and the diamond particle size in the second component unit is 60~100 mesh.

[0015] Experiments have shown that heterogeneous structures can achieve a controllable diamond arrangement by changing the radial and circumferential diamond concentration and particle size. During drilling, a "tooth-like" structure is gradually formed, which improves the wear resistance of weak areas such as the drill bit nozzle and inner and outer diameters, while effectively increasing the life of the drill bit and drilling efficiency.

[0016] In a further preferred embodiment, the fan-shaped segment is further divided into P annular structural blocks along the radial direction. The first component unit and the second component unit are aligned and spliced ​​or staggered in adjacent annular structural blocks, and the angle of the staggered arrangement is between 0° and 180°.

[0017] Experiments have shown that staggered arrangement can form a stepped free surface during drilling, significantly reducing the energy required for rock breaking; staggered arrangement blocks can continuously provide a high-stress zone similar to a cutting edge, and high-concentration blocks can also ensure the wear resistance of the drill bit. The synergistic effect of the two prevents slippage and avoids the problem of excessively rapid drill bit wear in low-concentration areas; staggered arrangement can significantly reduce vibration amplitude, improve drilling stability, and also reduce fatigue damage to drill pipes and drilling rigs.

[0018] In a further preferred embodiment, when the first component unit and the second component unit are staggered in adjacent annular structural blocks, the shapes of the first component unit and the second component unit are selected from polygons and arcs.

[0019] In a further preferred embodiment, the annular structural block is an annular structural block with a compositional gradient, and the diamond particle size in the first component layer is larger than the diamond particle size in the second component layer.

[0020] Experiments have shown that the impregnated diamond drill bit employs a composite heterogeneous design with a radial diamond concentration gradient and alternating circumferential particle size distribution. This precisely matches the working conditions in different areas of the drill bit, solving the inherent defects of traditional uniformly distributed drill bits, such as uneven wear inside and outside, low rock-breaking efficiency of single-particle-size, and poor adaptability to complex formations. Specifically, the radial gradient extends drill bit life, optimizes stress distribution, and enhances diameter retention by matching the differences in linear velocity and wear intensity of different radii. The alternating circumferential particle size achieves volumetric fracturing through a synergistic rock-breaking mechanism of large particle cutting and small particle smoothing, enhancing the drill bit's self-sharpening ability to solve slippage problems and dispersing cutting loads to improve drilling stability. The combination of these two elements forms an optimal three-dimensional spatial distribution, extending the overall drill bit life, increasing mechanical drilling speed, and improving the impact resistance of the matrix.

[0021] In a further preferred embodiment, when P is 4 to 8, the volume fraction of diamond in the outermost and innermost layers of the annular structure block is 60 to 80%, and then the volume fraction of diamond decreases by 10 to 40% layer by layer from the innermost and outermost layers toward the center. In this invention, the outermost and innermost layers of the annular structure block are the boundary portions of the outermost diameter of the sector segment boundary region.

[0022] For drilling in typical hard formations, the above-mentioned preferred scheme results in intense friction between the drill bit's inner and outer diameters and the borehole wall and core, leading to rapid wear. Increasing the diamond concentration can enhance wear resistance and reduce edge chipping or excessive wear. The central region, primarily responsible for rock breaking, benefits from a lower diamond concentration, which promotes timely diamond particle engagement, maintains cutting sharpness, improves rock-breaking efficiency, and prevents slippage due to excessive wear.

[0023] In a further preferred embodiment, when P is 9 to 30, the volume fraction of diamond in the outermost and innermost layers is 40 to 80%. Then, the volume fraction of diamond decreases by 3 to 30%, preferably 5 to 20%, from the innermost and outermost layers toward the center until the sub-center layer. Then, the volume fraction of diamond increases from the sub-center layer to the center layer by 3 to 30%, preferably 5 to 20%.

[0024] For drilling deep into hard rock formations or formations with alternating hard and soft rock, the above-mentioned preferred scheme results in the outer edge of the drill bit having the highest linear velocity (which increases with radius), leading to intense friction with the borehole wall; the inner layer is more susceptible to impact due to cuttings backflow. High diamond concentrations in both the inner and outer layers enhance wear resistance, preventing edge chipping or excessive wear and maintaining a stable borehole diameter. The sub-center region (between the high-concentration inner and outer zones and the center) has the lowest diamond concentration, making the matrix more prone to wear. This prompts diamond particles to "sharpen" promptly, maintaining sharp cutting ability and preventing slippage or thermal damage due to excessive matrix wear. The center region has the lowest linear velocity (approaching zero) but experiences concentrated drill pressure, making it particularly vulnerable to impact during hard rock cutting. Increasing the concentration in the center layer enhances compressive strength, preventing chipping due to stress concentration and avoiding premature diamond detachment at low concentrations.

[0025] The primary function of the sprue is to allow sufficient coolant to flow across the drill bit's working face, cooling the drill bit matrix and diamonds, removing rock dust, and lubricating the borehole wall and drill bit. If the sprue edge lacks sufficient wear resistance, it will rapidly wear down, deform, or even collapse under the scouring of rock dust carried by the high-speed fluid flow. This leads to changes in the sprue's shape and size, making it irregular, increasing fluid flow resistance, and preventing rock dust from being effectively flushed away from the cutting surface, causing it to accumulate at the bottom of the hole. Furthermore, excessive sprue abrasion prematurely exposes diamond particles located deep within the matrix. These diamonds are usually thickly encased and are washed away or detached before fully realizing their cutting potential. Improving the wear resistance of the sprue can effectively prevent these situations from occurring.

[0026] In a preferred embodiment, the volume fraction of diamond in the boundary region is 70-80%, and the volume fraction of diamond in the boundary region is 5% or more greater than the maximum volume fraction of diamond in the central region.

[0027] In a preferred embodiment, the width of the boundary region is 1.2mm to 3.2mm. In this invention, the width of the boundary region refers to the distance extending from the outer edges of each fan-shaped segment towards the central region to the boundary line between the boundary region and the central region; the width includes the radial outer width, the radial inner width, the circumferential width on both sides, and the axial width at both ends. In this invention, the thickness of each block, except for the boundary region, is 0.4mm to 2.8mm.

[0028] In a preferred embodiment, the metal matrix, by mass percentage, comprises: 5%–20% cobalt, 5%–15% nickel, 10%–20% iron, 3%–8% titanium, 2%–6% chromium, 1%–5% molybdenum, 20%–50% copper, 8%–15% tungsten, and 10%–50% tungsten carbide.

[0029] By controlling the composition of the metal matrix within the above-mentioned range, the metal matrix in the inner and outer diameters of the drill bit and the water inlet section utilizes its high toughness and strength to prevent the diamond particles from falling off prematurely. The metal matrix in the middle section has good bonding strength with the diamond particles, avoiding stress concentration that could lead to cracking of the drill bit matrix. In addition, the metal matrix of the present invention has good thermal conductivity to prevent the diamond particles from graphitizing due to overheating.

[0030] In a preferred embodiment, the height of the heterogeneous working layer is 10mm to 100mm.

[0031] In a preferred embodiment, the heterogeneous impregnated diamond drill bit consists of a drill bit body, a non-working layer disposed on the drill bit body, and a heterogeneous working layer disposed on the non-working layer.

[0032] This invention discloses a method for preparing a heterogeneous impregnated diamond drill bit. Based on the structure and composition of the heterogeneous working layer in the heterogeneous impregnated diamond drill bit, diamond particles of at least one particle size are prepared. The diamond particles are mixed with a binder and then sequentially kneaded, granulated, and drawn to obtain at least one set of diamond filament materials. A metal matrix is ​​prepared, and the metal matrix is ​​mixed with a binder and then sequentially kneaded, granulated, and drawn to obtain a metal matrix filament material. Then, using a 3D printing device with a multi-feed system, the diamond filament material and the metal matrix filament material are placed in two feed ports of the 3D printing device, respectively. Based on the model of the heterogeneous working layer, the feeding speed of the two filament materials is controlled by the feeding system, allowing the two filament materials to continuously enter the mixing chamber at different proportions for melting and mixing. Then, the mixture is extruded through a nozzle for deposition printing to obtain a heterogeneous working layer green blank. The heterogeneous working layer green blank is degreased to obtain a degreased heterogeneous working layer green blank, which is then sintered to obtain the heterogeneous impregnated diamond drill bit.

[0033] In a preferred embodiment, the metal matrix powder is obtained by mixing cobalt powder, nickel powder, iron powder, titanium powder, chromium powder, molybdenum powder, copper powder, tungsten powder, and tungsten carbide powder in a designed ratio.

[0034] In actual operation, a mixer is used for mixing.

[0035] In a preferred embodiment, the adhesive, by mass percentage, comprises the following components: styrene 10%–25%, styrene-butadiene block copolymer 10%–25%, dodecyltrimethylammonium chloride 5%–10%, polyoxymethylene 20%–40%, polyvinyl chloride 5%–15%, vinyl bis-stearamide 1%–4%, paraffin wax 1%–5%, and oleic acid 1%–5%.

[0036] In this invention, the binder formulation comprises styrene-based resins, styrene-butadiene block copolymers, and polyoxymethylene (POM) forming the main skeleton of the filament. Styrene segments impart stiffness, while butadiene elastic blocks provide flexibility and resilience to prevent brittle breakage during winding. The crystallinity of POM further enhances mechanical support, and polyvinyl chloride acts as an auxiliary skeleton to adjust melt viscosity and hardness, ensuring consistent printability for both types of filaments. Paraffin wax, vinyl bis-stearamide, and oleic acid form a plasticizer-lubricant system. Paraffin wax, as a low-melting-point plasticizer, significantly reduces the overall melt viscosity. Vinyl bis-stearamide anchors between resin molecules through polar amide groups and provides boundary lubrication through non-polar long chains, achieving internal lubrication and external demolding. Oleic acid both wets the material, promoting uniform crushing of feed particles and reducing interfacial tension. Dodecyltrimethylammonium chloride, as a cationic surfactant, forms a stable dispersion layer on the surface of diamond and metal powders through the electrostatic adsorption of long-chain alkyl cations. Oleic acid synergistically enhances wetting and steric hindrance, ensuring that the two types of powders are highly dispersed and do not agglomerate within their respective binder filaments. When these two filaments with identical binder matrices are heated and melted in the mixing chamber, the matrix compatibility promotes rapid intersolidation of the two melts. Under the shearing action in the chamber, paraffin and oleic acid further reduce the melt viscosity and interfacial tension, enabling diamond particles to achieve uniform secondary dispersion in the metal slurry, effectively overcoming segregation caused by density differences. At the same time, the stepwise thermal decomposition behavior of the binder components ensures that the filaments co-extruded from the mixing chamber maintain good extrusion flowability and forming accuracy, while also decomposing and escaping sequentially in the subsequent degreasing process. Then, through sintering, the metal matrix is ​​densified and the diamonds are firmly embedded, resulting in a uniformly dispersed and tightly bonded metal-diamond composite workpiece.

[0037] In a preferred embodiment, the mass fraction of the additive in the diamond filament material and the metal matrix filament material is 5% to 35%.

[0038] In the preferred embodiment, the mixing temperature is 100-500℃ and the mixing time is 0.2-1.5h.

[0039] In a preferred embodiment, the granulation temperature is 100–500°C and the rotation speed is 20–300 rpm.

[0040] In the preferred embodiment, the diameter of the columnar granules obtained from granulation is 1-10 mm and the length is 1-20 mm.

[0041] In a preferred embodiment, the drawing temperature is 120–300°C and the rotation speed is 20–200 rpm.

[0042] In actual operation, the material is mixed in an internal mixer, then granulated in a granulator, and finally drawn into wires in a wire drawing machine to obtain filaments containing diamond particles and matrix, and then wound up on a traction machine.

[0043] In a preferred embodiment, the diameters of both the diamond filament material and the metal matrix filament material are 0.5–5 mm. This invention requires controlling the diameter of the filament material within this range; if the diameter is too small, the filament material may break during feeding, interrupting the printing process.

[0044] By dynamically controlling the feed ratio of the two types of filaments into the extrusion end, the two are mixed in a variable ratio in the molten state, thereby achieving a non-uniform distribution of diamond concentration inside the working layer of the final formed impregnated diamond drill bit.

[0045] In a preferred embodiment, the temperature of the mixing chamber is controlled at 150~400℃, and stirring is applied within the mixing chamber at a speed of 30~300 rpm. Through stirring, the two filaments form a stable composite flow structure under the shearing and turbulence effects within the mixing chamber, resulting in uniform mixing.

[0046] In a preferred embodiment, during the 3D printing process, the printing speed is 20mm / s to 90mm / s, the printing layer thickness is 0.02mm to 1mm, and the printing temperature is 150℃ to 280℃.

[0047] In actual operation, printing parameters are first set, and a model of the heterogeneous working layer is drawn in the computer. The model is then imported into the slicing software to set the printing parameters, and then imported into the multi-nozzle melt extrusion printer. Diamond and matrix filaments are then independently placed into the printer's two filament feeding mechanisms. By dynamically controlling the feed ratio of the two filaments into the extrusion end, the two are mixed in a variable ratio in the molten state, thereby achieving a non-uniform distribution of diamond concentration inside the final formed impregnated diamond drill bit working layer. At the same time, according to the diamond particles of different sizes in different blocks, multiple sets of diamond filament materials with different diamond particle sizes are taken out and fed into the same feed port according to different block structures.

[0048] In a preferred embodiment, during the 3D printing process, radially varying layers are printed in order from the outer diameter to the inner diameter, and circumferentially varying layers are printed in order from both ends of the sprue to the center. After printing is completed, the printed part is placed into a mold according to the design requirements for degreasing treatment.

[0049] In a preferred embodiment, the degreasing process is carried out under hydrogen protection conditions, first by raising the temperature at 4–10°C / min to 90–110°C and holding for 1–1.5 hours; then by raising the temperature at 3–6°C / min to 200–240°C and holding for 2–2.5 hours; next by raising the temperature at 2–4°C / min to 350–380°C and holding for 0.5–1 hour; then by raising the temperature at 2.5–5°C / min to 430–470°C and holding for 1–1.5 hours; finally by raising the temperature at 2–3°C / min to 590–620°C and holding for 1–1.5 hours; followed by furnace cooling. In the thermal degreasing process of this invention, a gradient heating mode is used for step-by-step degreasing, which effectively ensures the integrity of the green blank and the removal of binders from the green blank, avoiding degreasing problems such as bulging, cracking, and excessive binder residue.

[0050] In a preferred embodiment, the non-working layer, the non-working layer, and the drill bit rigid body of the heterogeneous structure are assembled and then sintered. The sintering temperature is 850–1150℃, the pressure is 1–6 MPa, and the holding time is 3–30 min. After sintering, the parts are cooled and demolded.

[0051] The preferred method is to machine the blank obtained after sintering according to the design of a heterogeneous structure impregnated diamond drill bit to obtain a heterogeneous structure impregnated diamond drill bit.

[0052] In actual operation, the blank obtained after sintering is machined to mill threads, sprues, water grooves, etc., and then polished and packaged to obtain the heterogeneous structure impregnated diamond drill bit.

[0053] Beneficial effects

[0054] This invention provides a heterogeneous impregnated diamond drill bit. By controlling the diamond volume fraction in the heterogeneous working layer to be greater near the inner and outer diameters and the nozzle than in the center, the heterogeneous impregnated diamond drill bit can possess both excellent wear resistance and cutting efficiency, significantly extending its service life. The higher diamond concentration near the inner and outer diameters and the nozzle provides better wear resistance, adapting to the more intense friction and impact experienced by the inner and outer diameters during drilling as they directly contact the borehole wall and core. Meanwhile, the central portion, which undertakes the cutting task, uses a lower diamond concentration to achieve better cutting efficiency.

[0055] This invention provides a 3D printing method for manufacturing heterogeneous impregnated diamond drill bits. This technology enables precise diamond material placement and utilizes a multi-nozzle printer to achieve multi-layer vertical printing of thin diamond working layers, thus completing the fabrication of heterogeneous impregnated diamond drill bits. This method can significantly improve the production efficiency of heterogeneous impregnated diamond drill bits and reduce production costs. Attached Figure Description

[0056] Figure 1 A schematic diagram of the composition distribution of the heterogeneous impregnated diamond drill bit in Example 1.

[0057] Figure 2 A schematic diagram of the composition distribution of the heterogeneous impregnated diamond drill bit in Example 2. Not all layers are shown in the figure.

[0058] Figure 3 This is a schematic diagram of the heterogeneous structure impregnated diamond drill bit of the present invention, wherein 1 is the drill bit steel body and 2 is the heterogeneous structure working layer. Detailed Implementation

[0059] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments.

[0060] Example 1

[0061] The entire heterogeneous working layer is circumferentially distributed with 8 nozzle zones, which uniformly divide the heterogeneous working layer into multiple fan-shaped segments. Each fan-shaped segment includes a boundary region and a central region. The width of the entire boundary region is 2 mm, and the volume fraction of diamond in the boundary region is 80%.

[0062] In addition, the entire heterogeneous working layer's fan-shaped segment is further divided radially into 11 annular structural blocks. Except for the boundary region where the working layer thickness on both the inner and outer diameter sides is 2mm, the remaining working layer sheets have a thickness of 1.6mm and a working layer height of 30mm. The diamond volume fraction in the working layer sheets, from the outer diameter to the inner diameter, is 80%, 70%, 60%, 40%, 20%, 40%, 20%, 40%, 60%, 70%, and 80%, respectively. Correspondingly, the metal matrix volume content in the working layer sheets is 20%, 30%, 40%, 60%, 80%, 60%, 80%, 60%, 40%, 30%, and 20%.

[0063] The metal matrix in each working layer sheet, by mass percentage, is composed of: 10% cobalt, 10% nickel, 15% iron, 5% titanium, 5% chromium, 3% molybdenum, 25% copper, 10% tungsten, and 17% tungsten carbide.

[0064] In addition, the circumferential structure includes alternating first and second component units with different diamond particle sizes. The diamond particle size range in the first component unit is 20-50 mesh, and the diamond particle size range in the second component unit is 60-100 mesh. The first and second component units are polygonal blocks and are staggered in adjacent annular structural blocks.

[0065] Its manufacturing process is as follows:

[0066] (1) Weigh out cobalt powder, nickel powder, iron powder, titanium powder, chromium powder, molybdenum powder, copper powder, tungsten powder, tungsten carbide, etc. according to the formula calculation amount, and pour them into the mixer together with the additives and mix them evenly to obtain the matrix mixture. Pour two diamond particles of different sizes into the mixer together with the additives and mix them evenly to obtain two diamond mixtures.

[0067] The additives, by weight percentage, are composed of the following: styrene 20%, styrene-butadiene block copolymer 20%, dodecyltrimethylammonium chloride 5%, polyoxymethylene 30%, polyvinyl chloride 15%, vinyl bis-stearamide 3%, paraffin wax 2%, and oleic acid 5%. The additives constitute 20% of the total weight in all three mixtures.

[0068] (2) Set the internal mixer temperature to 195℃, and put the three mixtures into the internal mixer in sequence and mix for 1 hour;

[0069] (3) The two mixed materials are put into the pellet mill in sequence, the temperature is set to 200℃ and the rotation speed is set to 100rpm, and columnar particles with a diameter of 5mm and a length of 5mm are obtained.

[0070] (4) The prepared granules are put into the wire drawing machine in sequence, the temperature is set to 190℃ and the rotation speed is set to 80rpm to obtain a wire with a diameter of 5mm;

[0071] (5) First, use computer 3D modeling software to establish a heterogeneous structure impregnated diamond drill bit model, save the file in STL format, then use slicing software to slice the model and import it into the 3D printer; then input the parameters required for the 3D printing process into the computer control system, wherein the printing speed is set to 50mm / s, the printing temperature is set to 200℃, and the layer thickness is set to 0.3mm; then put the prepared diamond and matrix filaments into the two filament feeding mechanisms of the printer independently, and by dynamically controlling the feed ratio of the two filaments into the extrusion end, the two are mixed in a molten state in the mixing chamber with a variable ratio, and the temperature of the mixing chamber is controlled to be 200℃ and the rotation speed is 80rpm to obtain the working layer filament with the change in concentration. Print according to the model to obtain the heterogeneous structure working layer green blank.

[0072] (6) Place the printed working layer into a degreasing oven for degreasing. First, raise the temperature to 100℃ at 6℃ / min and hold for 1h; then raise the temperature to 220℃ at 4℃ / min and hold for 2.5h; then raise the temperature to 360℃ at 3℃ / min and hold for 0.5h; then raise the temperature to 470℃ at 5℃ / min and hold for 1.5h; finally raise the temperature to 620℃ at 2℃ / min and hold for 1.5h; then cool with the oven.

[0073] (7) Place the degreased material into a medium-frequency sintering furnace for sintering. The holding pressure is 4 MPa, the sintering temperature is 960℃, the holding time is 30 min, and then cool and demold.

[0074] (8) After the sintering and demolding of the drill bit sintered body, the threads, water inlet, water groove, etc. are machined, and then polished and packaged to obtain the heterogeneous structure impregnated diamond drill bit. The drill bit has a life of 170m and a drilling speed of 6m / h. No cracking of the matrix or slippage of the drill bit has occurred.

[0075] Example 2

[0076] The entire heterogeneous working layer is circumferentially distributed with 10 nozzle zones, which uniformly divide the heterogeneous working layer into multiple fan-shaped segments. Each fan-shaped segment includes a boundary region and a central region. The width of the entire boundary region is 3 mm, and the volume fraction of diamond in the boundary region is 80%.

[0077] In addition, the entire heterogeneous working layer's fan-shaped segment is further divided radially into six annular structural blocks. Except for the 3mm section in the boundary region, the remaining working layer sheets have a thickness of 2.5mm and a height of 40mm. The diamond volume fraction in the working layer sheets, from the outer diameter to the inner diameter, is 80%, 60%, 20%, 20%, 60%, and 80%, respectively. Correspondingly, the metal matrix volume content in the working layer sheets is 20%, 40%, 80%, 80%, 40%, and 20%, respectively.

[0078] In addition, the circumferential part includes alternating first component units and second component units with different diamond particle sizes, wherein the diamond particle size range of the first component unit is 20~50 mesh, and the diamond particle size range of the second component unit is 60~100 mesh, and the first component unit and the second component unit are aligned and spliced ​​together.

[0079] The metal matrix in each working layer sheet, by mass percentage, consists of: 5% cobalt, 5% nickel, 15% iron, 5% titanium, 5% chromium, 2% molybdenum, 35% copper, 10% tungsten, and 18% tungsten carbide.

[0080] Its manufacturing process is as follows:

[0081] (1) Weigh out cobalt powder, nickel powder, iron powder, titanium powder, chromium powder, molybdenum powder, copper powder, tungsten powder, tungsten carbide, etc. according to the formula calculation, and pour them into the mixer together with the additives and mix them evenly to obtain the matrix mixture. Pour diamond and the additives into the mixer together and mix them evenly to obtain the diamond mixture.

[0082] The additives, by weight percentage, are composed of the following: styrene 15%, styrene-butadiene block copolymer 25%, dodecyltrimethylammonium chloride 5%, polyoxymethylene 35%, polyvinyl chloride 10%, vinyl bis-stearamide 2%, paraffin wax 4%, and oleic acid 4%.

[0083] Furthermore, the mass fraction of the additive in both mixtures is 15%.

[0084] (2) Set the internal mixer temperature to 190℃, and put the two mixtures into the internal mixer in sequence for internal mixing;

[0085] (3) The two mixed materials are put into the pellet mill in sequence, the temperature is set to 190℃ and the rotation speed is set to 100rpm, and columnar particles with a diameter of 5mm and a length of 5mm are obtained.

[0086] (4) The prepared granules are put into the wire drawing machine in sequence, the temperature is set to 190℃ and the rotation speed is set to 80rpm to obtain wire with a diameter of 4mm;

[0087] (5) First, a heterogeneous structure impregnated diamond drill bit model is established using computer 3D modeling software. The file is saved in STL format. Then, the model is sliced ​​using slicing software and imported into the 3D printer. Then, the parameters required for the 3D printing process are input into the computer control system. The printing speed is set to 80 mm / s, the printing temperature is set to 190℃, and the layer thickness is set to 0.2 mm. Then, the prepared diamond and matrix filaments are independently placed into the two filament feeding mechanisms of the printer. By dynamically controlling the feed ratio of the two filaments into the extrusion end, the two are mixed in a variable proportion in the mixing chamber in a molten state. The temperature of the mixing chamber is controlled at 230℃ and the rotation speed is 120 rpm to obtain the working layer filament with varying concentration. The heterogeneous structure working layer green body is obtained by printing according to the model.

[0088] (6) Place the printed working layer into a degreasing oven for degreasing. First, raise the temperature to 100℃ at 5℃ / min and hold for 1h; then raise the temperature to 220℃ at 4℃ / min and hold for 2.5h; then raise the temperature to 360℃ at 3℃ / min and hold for 0.5h; then raise the temperature to 460℃ at 5℃ / min and hold for 1h; finally raise the temperature to 620℃ at 2℃ / min and hold for 1.5h; then cool with the oven.

[0089] (7) Place the degreased material into a medium-frequency sintering furnace for sintering. The holding pressure is 5 MPa, the sintering temperature is 1000℃, and the holding time is 20 min.

[0090] (8) After the sintering and demolding of the drill bit sintered body, the threads, water inlet, water groove, etc. are machined, and then polished and packaged to obtain the heterogeneous structure impregnated diamond drill bit. The drill bit has a life of 185m and a drilling speed of 4.5m / h. No cracking of the matrix or slippage of the drill bit has occurred.

[0091] Example 3

[0092] The entire heterogeneous working layer is circumferentially distributed with 10 nozzle zones, which uniformly divide the heterogeneous working layer into multiple fan-shaped segments. Each fan-shaped segment includes a boundary region and a central region. The width of the entire boundary region is 2.5 mm, and the volume fraction of diamond in the boundary region is 75%.

[0093] In addition, the entire heterogeneous working layer's fan-shaped segment is further divided into 7 annular structural blocks along the circumference. Except for the boundary region where the working layer thickness on both sides of the sprue is 2mm, the remaining working layer sheets are 1.5mm thick, with a working layer height of 35mm. The diamond volume fraction in the working layer sheets, from outer diameter to inner diameter, is 75%, 60%, 20%, 40%, 20%, 60%, and 75%, respectively. Correspondingly, the metal matrix volume content in the working layer sheets is 25%, 40%, 80%, 60%, 80%, 40%, and 25%.

[0094] The metal matrix in each working layer sheet, by mass percentage, consists of: 10% cobalt, 5% nickel, 20% iron, 5% titanium, 5% chromium, 3% molybdenum, 25% copper, 10% tungsten, and 17% tungsten carbide.

[0095] In addition, the radial part includes alternating first component units and second component units with different diamond particle sizes, wherein the diamond particle size range of the first component unit is 20~50 mesh, and the diamond particle size range of the second component unit is 60~100 mesh. The first component unit and the second component unit are polygonal blocks and are aligned in adjacent annular structural blocks.

[0096] Its manufacturing process is as follows:

[0097] (1) Weigh out cobalt powder, nickel powder, iron powder, titanium powder, chromium powder, molybdenum powder, copper powder, tungsten powder, tungsten carbide, etc. according to the formula calculation, and pour them into the mixer together with the additives and mix them evenly to obtain the matrix mixture. Pour diamond and the additives into the mixer together and mix them evenly to obtain the diamond mixture.

[0098] The additives, by mass percentage, are composed of the following: styrene 15%, styrene-butadiene block copolymer 20%, dodecyltrimethylammonium chloride 10%, polyoxymethylene 30%, polyvinyl chloride 15%, vinyl bis-stearamide 3%, paraffin wax 3%, and oleic acid 4%.

[0099] Furthermore, the mass fraction of the additive in both mixtures is 15%.

[0100] (2) Set the internal mixer temperature to 195℃, and put the two mixtures into the internal mixer in sequence and mix for 1.5h;

[0101] (3) The two mixed materials are put into the pellet mill in sequence, the temperature is set to 200℃ and the rotation speed is set to 100rpm, and columnar particles with a diameter of 3mm and a length of 5mm are obtained.

[0102] (4) The prepared granules are put into the wire drawing machine in sequence, the temperature is set to 190℃ and the rotation speed is set to 80rpm to obtain a wire with a diameter of 5mm;

[0103] (5) First, use computer 3D modeling software to establish a heterogeneous structure impregnated diamond drill bit model, save the file in STL format, then use slicing software to slice the model and import it into the 3D printer; then input the parameters required for the 3D printing process into the computer control system, wherein the printing speed is set to 60mm / s, the printing temperature is set to 200℃, and the layer thickness is set to 0.3mm; then put the prepared diamond and matrix filaments into the two filament feeding mechanisms of the printer independently, and by dynamically controlling the feed ratio of the two filaments into the extrusion end, the two are mixed in a variable ratio in the molten state in the mixing chamber. The temperature of the mixing chamber is controlled to be 220℃ and the rotation speed is 100rpm to obtain the working layer filament with the change in concentration. Print according to the model to obtain the heterogeneous structure working layer green body;

[0104] (6) Assemble the printed working layer sheets in sequence and place them in a degreasing oven for degreasing. First, raise the temperature to 110℃ at 8℃ / min and hold for 1 hour; then raise the temperature to 220℃ at 5℃ / min and hold for 2 hours; then raise the temperature to 370℃ at 4℃ / min and hold for 1 hour; then raise the temperature to 470℃ at 5℃ / min and hold for 1.5 hours; finally, raise the temperature to 620℃ at 3℃ / min and hold for 1.5 hours; then cool with the oven.

[0105] (7) Place the degreased material into a medium-frequency sintering furnace for sintering. The holding pressure is 8 MPa, the sintering temperature is 900℃, and the holding time is 30 min.

[0106] (8) After the sintering and demolding of the drill bit sintered body, the threads, sprue, and water groove are machined, and then polished and packaged to obtain the heterogeneous structure impregnated diamond drill bit. The drill bit has a life of 165m and a drilling speed of 4.5m / h. No cracking of the matrix or slippage of the drill bit has occurred.

[0107] Comparative Example 1

[0108] All other conditions were the same as in Example 1, except for two concentration variations: the inner and outer diameter portions had a diamond powder content of 60% and a metal powder content of 40%; the middle layer had a diamond powder content of 30% and a metal powder content of 70%. Due to the limited number of concentration variations, the wear resistance of the drill bit could not be effectively improved, and the drill bit's service life was only 80m.

[0109] Comparative Example 2

[0110] All other conditions were the same as in the previous example, but instead of using a stepped heating method during the degreasing process, the temperature was increased to 600°C at a rate of 10°C / min. As a result, the degreased blank bulged and cracked, making it impossible to obtain a non-homogeneous structure impregnated diamond drill bit of acceptable quality.

[0111] Comparative Example 3

[0112] All other conditions were the same as in Example 3, except that the matrix formulation was changed. By mass percentage, its composition was: cobalt 20%, titanium 5%, chromium 5%, copper 40%, tungsten 10%, and tungsten carbide 20%. The mechanical strength of the drill bit was reduced, and the drilling life was only 60m.

Claims

1. A heterogeneous impregnated diamond drill bit, characterized in that: The heterogeneous structure impregnated diamond drill bit includes a heterogeneous structure working layer, which is composed of diamond and a metal matrix. The heterogeneous structure working layer has a ring structure with several sprue zones distributed circumferentially around the entire ring structure, uniformly dividing the heterogeneous structure working layer into multiple fan-shaped segments. Each fan-shaped segment includes a boundary region and a central region. The boundary region is set around the entire edge of the fan-shaped segment, wherein the volume fraction of diamond in the boundary region is greater than the volume fraction of diamond in the central region. Each fan-shaped segment also contains several blocks with different compositions or different particle sizes.

2. The heterogeneous impregnated diamond drill bit according to claim 1, characterized in that: The fan-shaped segment is further provided with N annular blocks in the radial direction. The annular blocks include a first component block and a second component block. The first component block and the second component block are nested alternately in the radial direction. The volume fraction of diamond in the first component block is greater than the volume fraction of diamond in the second component block and / or the particle size of diamond in the first component block is greater than the particle size of diamond in the second component block. When the volume fraction of diamond in the first component block is greater than the volume fraction of diamond in the second component block, the volume fraction of diamond in the first component block is 60% to 80%, and the volume fraction of diamond in the second component block is 6% to 40%. When the diamond particle size in the first component block is larger than that in the second component block, the diamond particle size in the first component block is 20~50 mesh, and the diamond particle size in the second component block is 60~100 mesh.

3. The heterogeneous impregnated diamond drill bit according to claim 1, characterized in that: The fan-shaped segment is further provided with M unit blocks along the circumferential direction. Each unit block includes a first component unit and a second component unit. The first component unit and the second component unit are alternately arranged along the circumferential direction. The volume fraction of diamond in the first component unit is greater than the volume fraction of diamond in the first component unit and / or the particle size of diamond in the first component unit is greater than the particle size of diamond in the first component unit. When the volume fraction of diamond in the first component unit is greater than the volume fraction of diamond in the second component unit, the volume fraction of diamond in the first component unit is 60% to 80%, and the volume fraction of diamond in the second component unit is 6% to 40%. When the diamond particle size in the first component unit is larger than that in the second component unit, the diamond particle size in the first component unit is 20~50 mesh, and the diamond particle size in the second component unit is 60~100 mesh.

4. A heterogeneous impregnated diamond drill bit according to claim 3, characterized in that: The sector segment is further divided into P annular structural blocks along the radial direction. The first component unit and the second component unit are aligned and spliced ​​or staggered in adjacent annular structural blocks. The angle of the staggered arrangement is between 0° and 180°.

5. A heterogeneous impregnated diamond drill bit according to claim 4, characterized in that: The annular structure layer is an annular structure block with a compositional gradient, and the diamond particle size in the first component layer is larger than that in the second component layer. When P is 4 to 8, the volume fraction of diamond in the outermost and innermost layers is 60 to 80%, and then the volume fraction of diamond decreases by 10 to 40% layer by layer from the innermost and outermost layers toward the center. When P is 9 to 30, the volume fraction of diamond in the outermost and innermost layers is 40 to 80%. Then, the volume fraction of diamond decreases by 3 to 30% from the innermost and outermost layers toward the center. After reaching the sub-center layer, the volume fraction increases by 3 to 30% from the sub-center layer back to the center layer.

6. A heterogeneous impregnated diamond drill bit according to any one of claims 1-3, characterized in that: In the boundary region, the volume fraction of diamond is 70-80%, and the volume fraction of diamond in the boundary region is 5% or more greater than the maximum volume fraction of diamond in the central region. The width of the boundary region is 1.2mm to 3.2mm. The metal matrix, by mass percentage, is composed of: 5%–20% cobalt, 5%–15% nickel, 10%–20% iron, 3%–8% titanium, 2%–6% chromium, 1%–5% molybdenum, 20%–50% copper, 8%–15% tungsten, and 10%–50% tungsten carbide.

7. A method for preparing a heterogeneous impregnated diamond drill bit according to any one of claims 1-4, characterized in that: Based on the structure and composition of the heterogeneous working layer in a heterogeneous impregnated diamond drill bit, diamond particles of at least one particle size are prepared. After mixing the diamond particles with a binder, the mixture is successively kneaded, granulated, and drawn to obtain at least one set of diamond filament materials. A metal matrix is ​​prepared, and after mixing the metal matrix with a binder, the mixture is successively kneaded, granulated, and drawn to obtain a metal matrix filament material. Then, using a 3D printing equipment with a multi-feed system, the diamond filament material and the metal matrix filament material are placed in two feed ports of the 3D printing equipment, respectively. Based on the model of the heterogeneous working layer, the feeding speed of the two filament materials is controlled by the feeding system, so that the two filament materials are continuously fed into the mixing chamber at different proportions to melt and mix. Then, the mixture is extruded and deposited through a nozzle to obtain a heterogeneous working layer green body. The heterogeneous working layer green body is degreased to obtain a degreased heterogeneous working layer green body, which is then sintered to obtain a heterogeneous impregnated diamond drill bit.

8. The method for preparing a heterogeneous impregnated diamond drill bit according to claim 7, characterized in that: The adhesive, by mass percentage, comprises the following components: styrene 10%–25%, styrene-butadiene block copolymer 10%–25%, dodecyltrimethylammonium chloride 5%–10%, polyoxymethylene 20%–40%, polyvinyl chloride 5%–15%, vinyl bis-stearamide 1%–4%, paraffin wax 1%–5%, and oleic acid 1%–5%. In the diamond filament material and the metal matrix filament material, the mass fraction of the additive is 5% to 35%; The mixing temperature is 100–500℃, and the mixing time is 0.2–1.5 h. The granulation temperature is 100–500℃ and the rotation speed is 20–300 rpm. The diameter of the columnar granules obtained by granulation is 1-10 mm and the length is 1-20 mm. The drawing temperature is 120-300℃ and the rotation speed is 20-200rpm. The diameters of both diamond filaments and metal matrix filaments are 0.5–5 mm.

9. The method for preparing a heterogeneous impregnated diamond drill bit according to claim 7, characterized in that: The temperature of the mixing chamber is controlled at 150~400℃, and stirring is applied in the mixing chamber, with the stirring speed controlled at 30~300rpm; During the 3D printing process, the printing speed is 20mm / s to 90mm / s, the printing layer thickness is 0.02mm to 1mm, and the printing temperature is 150℃ to 280℃. During the 3D printing process, in the radial direction, printing is performed in the order from the outer diameter to the inner diameter; in the circumferential direction, printing is performed in the order from the sprue to the center.

10. The method for preparing a heterogeneous impregnated diamond drill bit according to claim 7, characterized in that: The degreasing process is carried out under hydrogen protection conditions. First, the temperature is increased to 90-110°C at a rate of 4-10°C / min and held for 1-1.5 hours; then, it is increased to 200-240°C at a rate of 3-6°C / min and held for 2-2.5 hours; next, it is increased to 350-380°C at a rate of 2-4°C / min and held for 0.5-1 hour; then, it is increased to 430-470°C at a rate of 2.5-5°C / min and held for 1-1.5 hours; finally, it is increased to 590-620°C at a rate of 2-3°C / min and held for 1-1.5 hours; then, it is cooled in the furnace. The non-working layer, the degreased blank of the heterogeneous structure working layer, and the drill bit rigid body are assembled and then sintered. The sintering temperature is 850-1150℃, the pressure is 1-6MPa, and the holding time is 3-30min.

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