Diamond compact and applications and methods of making

Abstract

The present application provides a kind of diamond compact and application and preparation method, including hard alloy base and the diamond composite layer being arranged on the top surface of the hard alloy base, the diamond composite layer includes the working layer for cutting;Wherein, the material of the working layer includes first binder and the diamond powder of granularity 10-40 μm, 4-8 μm and 1-4 μm.This application has good impact resistance and wear resistance and can effectively take away the heat generated when cutting rock, improve the service life of the compact.

Description

Technical Field

[0001] This invention relates to diamond composite sheets, their applications, and preparation methods. Background Technology

[0002] In the late 1970s, diamond drill bits were widely used in oil and gas extraction due to their superior performance. These drill bits mainly include synthetic polycrystalline diamond (PDC) drill bits, heat-stabilized polycrystalline diamond (TSP) drill bits, and natural diamond drill bits. Initially, PDC drill bits were primarily used in soft to medium-hard formations. After decades of development, their performance has been significantly improved, and they are now widely used in hard formations, becoming the most commonly used drill bits in the oil and gas extraction industry.

[0003] The volcanic strata of the Songliao Basin are characterized by high quartz content, high compressive strength, and strong abrasiveness. Rich in basalt, andesite, rhyolite, tuff, and volcanic breccia, the rocks exhibit significant hardness variations, with compressive strength exceeding 300 MPa and a drillability of 7-10 on the extreme hardness scale. This makes PDC (polycrystalline diamond) composite inserts highly susceptible to tooth breakage, drastically shortening drill bit life and limiting single-bit drilling footage to rarely exceeding 300 meters, with average mechanical drilling speeds below 3 m / h. Therefore, there is an urgent need to develop a PDC composite insert with strong impact resistance and wear resistance to improve mechanical drilling speed and single-bit footage. Currently, the industry commonly uses polycrystalline diamond composite layers in shapes such as spherical, conical, and ridged to enhance their impact resistance. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of insufficient impact resistance and wear resistance of conventional polycrystalline diamond composite sheets in volcanic rock formations, and the performance degradation of composite sheets due to high heat generation during rock cutting. This invention provides a diamond composite sheet, its application, and a preparation method that have good impact resistance and wear resistance and can effectively remove the heat generated during rock cutting, thereby improving the service life of the composite sheet.

[0005] To achieve the above objectives, the present invention provides a diamond composite sheet, comprising a cemented carbide substrate and a diamond composite layer disposed on the top surface of the cemented carbide substrate, wherein the diamond composite layer includes a working layer for cutting.

[0006] The working layer is made of a first binder and diamond micro powder with particle sizes of 10–40 μm, 4–8 μm and 1–4 μm.

[0007] Preferably, the material of the working layer includes a first binder and diamond micro powder with particle sizes of 10-30 μm, 4-6 μm and 1-2 μm.

[0008] Preferably, the material of the working layer comprises, by weight percentage: 80-85% diamond micropowder of 10-40 μm, 5-10% diamond micropowder of 4-8 μm, 1-3% diamond micropowder of 1-4 μm, and 3-5% of a first binder;

[0009] More preferably, the material of the working layer comprises, by weight percentage, 80-85% diamond micropowder of 10-40 μm, 5-10% diamond micropowder of 4-8 μm, 1-3% diamond micropowder of 1-4 μm, and 3-5% of a first binder.

[0010] Preferably, the diamond composite layer includes a transition layer located between the working layer and the top surface of the cemented carbide substrate;

[0011] More preferably, the material of the transition layer includes a second binder and diamond micro powder with particle sizes of 30–60 μm, 8–12 μm, and 2–6 μm;

[0012] Preferably, the diamond micro powder includes synthetic diamond micro powder.

[0013] Preferably, the first adhesive and the second adhesive are the same or different; more preferably, the first adhesive and the second adhesive include cobalt powder.

[0014] Preferably, the material of the transition layer comprises, by weight percentage: 80-90% of 30-60μm diamond powder, 5-15% of 8-12μm diamond powder, 1-5% of 2-6μm diamond powder, and 3-5% of a second binder;

[0015] More preferably, the material of the transition layer comprises, by weight percentage, 80-90% of 30-50μm diamond powder, 5-15% of 8-12μm diamond powder, 1-5% of 2-4μm diamond powder, and 3-5% of a second binder.

[0016] Preferably, the end face of the working layer has at least two protruding gradient planes, each of which extends from the edge of the working layer and converges at the middle of the end face, and the width of the gradient plane gradually increases from the edge of the composite sheet to the middle of the end face;

[0017] More preferably, the ratio of the width of the gradient plane at the edge of the composite sheet to the width at the center is (1-3):4;

[0018] Further preferably, the width of the gradient plane at the edge of the composite sheet is 2-4 mm, and the width of the gradient plane at the middle is 4-8 mm.

[0019] Preferably, at least two of the gradient planes are evenly distributed circumferentially;

[0020] More preferably, the angle θ between each of the gradient planes and the top surface of the cemented carbide substrate is 10° to 20°, and even more preferably 15° to 18°.

[0021] Preferably, the diamond composite layer is provided with a heat dissipation surface;

[0022] More preferably, the heat dissipation surface is configured as a concave curved surface located at the center of the diamond composite layer;

[0023] Further preferred is a ratio of the maximum cross-sectional area of ​​the concave curved surface to the cross-sectional area of ​​the diamond composite layer of (1-2):3.

[0024] Preferably, a wing surface that gradually slopes downward from the center to the edge is provided between two adjacent gradient planes, and the transition curvature radius of the wing surface and the gradient plane is 0.6 to 1 mm.

[0025] Preferably, the radius of curvature of the transition between the gradient plane and the concave surface is 0.6 to 1 mm.

[0026] Preferably, the edges of the diamond composite layer are chamfered.

[0027] Preferably, the diamond composite layer is a polycrystalline diamond composite layer.

[0028] Preferably, the top surface of the cemented carbide substrate is a concave-convex surface, a flat surface, or a grooved surface.

[0029] Preferably, the cross-section of the diamond composite sheet is circular or elliptical.

[0030] The second aspect of the present invention provides the application of the diamond composite sheet described herein in oil and gas extraction, preferably in drilling in volcanic rock formations.

[0031] The third aspect of the present invention provides a method for preparing a diamond composite sheet, comprising: mixing a first binder with diamond micro powder having particle sizes of 10-40 μm, 4-8 μm and 1-4 μm to obtain a working layer mixture; and loading the working layer mixture and the cemented carbide matrix into a mold for sintering to obtain a diamond composite sheet.

[0032] Preferably, the present invention includes: mixing a second binder with diamond micropowder with particle sizes of 30-60 μm, 8-12 μm and 2-6 μm to obtain a transition layer mixture, and loading the transition layer mixture, the working layer mixture and the cemented carbide substrate together into a mold for sintering, wherein the transition layer mixture is placed between the working layer and the cemented carbide substrate.

[0033] Preferably, the working layer mixture includes a first binder and diamond micropowder with particle sizes of 10–30 μm, 4–6 μm, and 1–2 μm.

[0034] Preferably, the transition layer mixture includes a second binder and diamond microparticles with particle sizes of 30–50 μm, 8–12 μm, and 2–4 μm.

[0035] Preferably, the diamond micro powder includes synthetic diamond micro powder.

[0036] Preferably, the first adhesive and the second adhesive comprise cobalt powder.

[0037] Preferably, the sintering conditions include: temperature 1520~1680℃, pressure 7.8~8.5GPa, and sintering time 0.5~1 hour.

[0038] Preferably, the working layer mixture comprises, by weight percentage: 80-85% synthetic diamond powder of 10-40 μm, 5-10% synthetic diamond powder of 4-8 μm, 1-3% synthetic diamond powder of 1-4 μm, and 3-5% cobalt powder.

[0039] More preferably, the working layer mixture comprises, by weight percentage, 80-85% synthetic diamond micropowder of 10-30 μm, 5-10% synthetic diamond micropowder of 4-6 μm, 1-3% synthetic diamond micropowder of 1-2 μm, and 3-5% cobalt powder.

[0040] Preferably, the transition layer mixture comprises, by weight percentage, 80-90% of 30-60μm synthetic diamond powder, 5-15% of 8-12μm synthetic diamond powder, 1-5% of 2-6μm synthetic diamond powder, and 3-5% of cobalt powder;

[0041] More preferably, the transition layer mixture comprises, by weight percentage, 80-90% of 30-50μm synthetic diamond powder, 5-15% of 8-12μm synthetic diamond powder, 1-5% of 2-4μm synthetic diamond powder, and 3-5% of cobalt powder.

[0042] Compared with the prior art, the diamond composite sheet provided by the present invention has the following advantages:

[0043] 1. The working layer in this invention can improve the impact and wear resistance of diamond composite sheets, making it suitable for drilling in high-strength volcanic rock formations.

[0044] 2. In the preferred embodiment, the multiple gradient planes are set as the cutting surfaces of the composite sheet, which gives the cutting surfaces a strong plowing effect, improves the crushing and drilling performance of the composite sheet, reduces the drilling and cutting resistance, and thus improves the mechanical drilling speed of the diamond drill bit.

[0045] 3. In the preferred embodiment, the cutting surface of the composite sheet of the present invention gradually wears down during the drilling process, and the cutting area gradually increases, so that it has good attack capability in the early stage, and good impact resistance in the later stage while ensuring a certain attack capability, thus having better formation adaptability.

[0046] 4. In the preferred embodiment, the cutting surface composed of the gradient plane and the wing surface also has strong impact resistance and can guide the rock cuttings at the bottom of the well to be discharged, further improving the mechanical drilling speed of the diamond drill bit and further enhancing the impact resistance of the composite sheet.

[0047] 5. In a preferred embodiment, it has multiple cutting surfaces, and after one cutting surface is worn, it can be rotated to another unworn surface for continued use.

[0048] 6. In the preferred embodiment, the concave curved surface in the center has a larger fluid contact area, which can more effectively remove the heat generated when cutting rocks and improve the service life of the composite sheet. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of a diamond composite sheet according to a specific embodiment of the present invention;

[0050] Figure 2 yes Figure 1 Top view of a medium diamond composite sheet;

[0051] Figure 3 yes Figure 2 A schematic diagram of the AA section;

[0052] Figure 4 yes Figure 2 Schematic diagram of the CC section;

[0053] Figure 5 This is a schematic diagram of the structure of a common diamond composite sheet.

[0054] Explanation of reference numerals in the attached figures

[0055] 101 Diamond composite layer; 102 Hard alloy matrix; 103 Gradient plane; 104 Airfoil; 109 Concave curved surface. Detailed Implementation

[0056] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0057] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0058] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "left," and "right" generally refer to the upper, lower, left, and right as shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0059] The first aspect of the present invention provides a diamond composite sheet, including a cemented carbide substrate 102 and a diamond composite layer 101 disposed on the top surface of the cemented carbide substrate 102, wherein the diamond composite layer 101 includes a working layer for cutting.

[0060] The working layer consists of a first binder and diamond micropowder with particle sizes of 10–40 μm, 4–8 μm, and 1–4 μm.

[0061] The working layer in this invention can improve the impact and wear resistance of diamond composite sheets, making it suitable for drilling in high-strength volcanic rock formations.

[0062] According to a preferred embodiment of the present invention, the material of the working layer includes a first binder and diamond micro powder with particle sizes of 10-30 μm, 4-6 μm and 1-2 μm.

[0063] According to a preferred embodiment of the present invention, the material of the working layer comprises, by weight percentage, 80-85% diamond micropowder of 10-40 μm, 5-10% diamond micropowder of 4-8 μm, 1-3% diamond micropowder of 1-4 μm, and 3-5% of a first binder.

[0064] According to a preferred embodiment of the present invention, the material of the working layer preferably comprises, by weight percentage, 80-85% diamond micropowder of 10-30 μm, 5-10% diamond micropowder of 4-6 μm, 1-3% diamond micropowder of 1-2 μm, and 3-5% of a first binder.

[0065] To further improve the impact resistance and wear resistance of diamond composite sheets, according to a preferred embodiment of the present invention, the diamond composite layer 101 includes a transition layer located between the working layer and the top surface of the cemented carbide substrate.

[0066] According to a preferred embodiment of the present invention, the material of the transition layer preferably includes a second binder and diamond micropowder with particle sizes of 30-60 μm, 8-12 μm and 2-6 μm.

[0067] According to a preferred embodiment of the present invention, the material of the transition layer more preferably includes a second binder and diamond micro powder with particle sizes of 30-50 μm, 8-12 μm and 2-4 μm.

[0068] According to a preferred embodiment of the present invention, the material of the transition layer preferably comprises, by weight percentage: 80-90% of 30-60 μm diamond powder, 5-15% of 8-12 μm diamond powder, 1-5% of 2-6 μm diamond powder, and 3-5% of a second binder.

[0069] According to a preferred embodiment of the present invention, the material of the transition layer more preferably comprises, by weight percentage, 80-90% of 30-50 μm diamond powder, 5-15% of 8-12 μm diamond powder, 1-5% of 2-4 μm diamond powder, and 3-5% of a second binder.

[0070] In this invention, diamond micro powder includes synthetic diamond micro powder.

[0071] In this invention, the first adhesive and the second adhesive may be the same or different; preferably, the first adhesive and the second adhesive include cobalt powder.

[0072] According to a preferred embodiment of the present invention, the end face of the working layer has at least two protruding gradient planes 103, each gradient plane 103 extending from the edge of the working layer and converging at the middle of the end face, and the width of the gradient plane 103 gradually increases from the edge of the composite sheet to the middle of the end face.

[0073] The diamond composite sheet prepared by the formulation of this invention has multiple gradient planes as the cutting surface of the composite sheet, which gives the cutting surface a strong plowing effect, improves the breaking and drilling performance of the composite sheet, reduces drilling cutting resistance, and thus increases the mechanical drilling speed of the diamond drill bit. At the same time, the cutting surface of the composite sheet of this invention gradually wears down during the drilling process, and the cutting area gradually increases, giving it good attack capability in the early stage, while maintaining a certain attack capability in the later stage while having good impact resistance, thus having better formation adaptability. With multiple cutting surfaces, after one cutting surface wears down, it can be rotated to another unworn surface for continued use, thereby reducing the operating cost of the drill bit.

[0074] To further improve the cutting performance of diamond composite sheets, according to a preferred embodiment of the present invention, the ratio of the width of the gradient plane 103 at the edge of the composite sheet to the width at the center is preferably 1 to 3:4.

[0075] According to a preferred embodiment of the present invention, more preferably, the width of the gradient plane 103 at the edge of the composite sheet is 2 to 4 mm, and the width of the gradient plane 103 at the middle is 4 to 8 mm.

[0076] According to a preferred embodiment of the present invention, at least two gradient planes 103 are evenly distributed circumferentially, that is, the central angles between two adjacent gradient planes are equal.

[0077] According to a preferred embodiment of the present invention, the angle θ between each gradient plane 103 and the top surface of the cemented carbide substrate 102 is preferably 10° to 20°, more preferably 15° to 18°.

[0078] According to a preferred embodiment of the present invention, the diamond composite layer 101 is provided with a heat dissipation surface, which improves the performance of the composite bit by reducing the performance degradation caused by the large amount of heat generated during the cutting of volcanic rock formations. Preferably, the heat dissipation surface is a concave curved surface 109 located at the center of the diamond composite layer. The concave curved surface has a larger fluid contact area, which can more effectively remove the heat generated during rock cutting and improve the service life of the composite bit. More preferably, the ratio of the maximum cross-sectional area of ​​the concave curved surface 109 to the cross-section of the diamond composite layer 101 is 1 to 2:3.

[0079] According to a preferred embodiment of the present invention, a wing surface 104 that gradually slopes downward from the center to the edge is provided between two adjacent gradient planes 103. In this way, the cutting surface formed by the gradient plane and the wing surface also has strong impact resistance and can guide the rock cuttings at the bottom of the well to be discharged, further improving the mechanical drilling speed of the diamond drill bit and further enhancing the impact resistance of the composite sheet. The transition radius of curvature between the wing surface 104 and the gradient plane 103 is 0.6 to 1 mm.

[0080] According to a preferred embodiment of the present invention, the transition radius of curvature between the gradient plane 103 and the concave curved surface 109 is 0.6 to 1 mm.

[0081] In this invention, the edge of the diamond composite layer 101 has a chamfer of 0.2 mm.

[0082] In this invention, the diamond composite layer 101 is a polycrystalline diamond composite layer.

[0083] In this invention, the top surface of the cemented carbide substrate 102 is a concave-convex surface, a flat surface, or a grooved surface; that is, the bonding surface between the transition layer and the cemented carbide is a concave-convex surface, a flat surface, or a grooved surface.

[0084] In this invention, the cross-section of the diamond composite sheet is circular or elliptical, preferably with a diameter of 13 to 18 mm.

[0085] The second aspect of the present invention provides the application of the diamond composite sheet described herein in oil and gas extraction, preferably in drilling in volcanic rock formations.

[0086] The third aspect of the present invention provides a method for preparing a diamond composite sheet, comprising: mixing a first binder with diamond micro powder having particle sizes of 10-40 μm, 4-8 μm and 1-4 μm to obtain a working layer mixture; loading the working layer mixture and a cemented carbide matrix into a mold for sintering to obtain a diamond composite sheet blank; and processing it into the aforementioned diamond composite sheet structure using existing technology.

[0087] According to a preferred embodiment of the present invention, the present invention includes: mixing a second binder with diamond micro powder having particle sizes of 30-60 μm, 8-12 μm and 2-6 μm to obtain a transition layer mixture, and loading the transition layer mixture, the working layer mixture and the cemented carbide substrate together into a mold for sintering, wherein the transition layer mixture is placed between the working layer and the cemented carbide substrate.

[0088] In this invention, the working layer mixture includes a first binder and diamond micro powder with particle sizes of 10–30 μm, 4–6 μm, and 1–2 μm.

[0089] In this invention, the transition layer mixture includes a second binder and diamond micropowder with particle sizes of 30–50 μm, 8–12 μm, and 2–4 μm.

[0090] In this invention, the first binder and the second binder include cobalt powder.

[0091] In this invention, the sintering conditions include: temperature 1520~1680℃, pressure 7.8~8.5GPa, and sintering time 0.5~1 hour.

[0092] According to a preferred embodiment of the present invention, the working layer mixture comprises, by weight percentage, 80-85% synthetic diamond micropowder of 10-40 μm, 5-10% synthetic diamond micropowder of 4-8 μm, 1-3% synthetic diamond micropowder of 1-4 μm, and 3-5% cobalt powder.

[0093] According to a preferred embodiment of the present invention, the working layer mixture preferably comprises, by weight percentage, 80-85% synthetic diamond micropowder of 10-30 μm, 5-10% synthetic diamond micropowder of 4-6 μm, 1-3% synthetic diamond micropowder of 1-2 μm, and 3-5% cobalt powder.

[0094] According to a preferred embodiment of the present invention, the transition layer mixture comprises, by weight percentage, 80-90% of 30-60 μm synthetic diamond powder, 5-15% of 8-12 μm synthetic diamond powder, 1-5% of 2-6 μm synthetic diamond powder, and 3-5% of cobalt powder.

[0095] According to a preferred embodiment of the present invention, the transition layer mixture preferably comprises, by weight percentage, 80-90% of 30-50 μm synthetic diamond powder, 5-15% of 8-12 μm synthetic diamond powder, 1-5% of 2-4 μm synthetic diamond powder, and 3-5% of cobalt powder.

[0096] The advantages of the present invention are illustrated below through examples, but the present invention is not limited thereto.

[0097] The impact resistance test method in the following embodiments is as follows: The specimen is fixed in the impact mold, the initial counterweight of the impact hammer is 20kg, the initial height is 15cm, and then the height is increased by 5cm each time, with a maximum height of 25cm, until the specimen is destroyed, and the number of impacts is recorded; The wear resistance test method is as follows: On the lathe, the linear speed of the specimen is set to 100m / min, the depth of cut is 0.3mm, the back slope angle is 20°, the feed is 3mm / r, and the fixture is removed after every 40 turns. The ground joint of the composite sheet is photographed, and its area is tested and recorded, until the number of turns reaches 160 or the ground joint reaches the base.

[0098] Example 1

[0099] Methods for preparing diamond composite sheets include:

[0100] 1) By weight percentage, 82% of 20μm synthetic diamond powder, 10% of 5μm synthetic diamond powder, 3% of 1.5μm synthetic diamond powder and 5% of cobalt powder are mixed to form a working layer mixture.

[0101] 2) By weight percentage, 88% of 40μm synthetic diamond powder, 6% of 10μm synthetic diamond powder, 2% of 3μm synthetic diamond powder and 4% of cobalt powder are mixed to form a transition layer mixture.

[0102] A cemented carbide matrix, a transition layer mixture, and a working layer mixture are sequentially loaded into a mold along the axial direction and sintered at a temperature of 1600℃ and a pressure of 8.2 GPa for 0.75 hours to obtain a diamond composite blank. The polycrystalline diamond composite sheet with the following structure is then prepared by machining using existing technology.

[0103] Among them, such as Figures 1-4 As shown, the diamond composite sheet includes a diamond composite layer 101 and a cemented carbide substrate 102. The diamond composite layer includes a transition layer and a working layer. The end face of the working layer has three gradient planes 103. Each gradient plane extends from the edge of the composite layer and converges at the center of the end face. The three gradient planes are evenly distributed circumferentially, that is, the central angle between two adjacent gradient planes is 120°.

[0104] The diamond composite layer has a concave curved surface 109 at the center of its end face. In this embodiment, the edge width of the three gradient planes is 2 mm, the width at the center of the end face is 4 mm, and the angle θ between each gradient plane 103 and the top surface of the cemented carbide substrate 102 is 15°. The radial cross-section of the diamond composite sheet is circular with a diameter of 15.8 mm. The edges of the diamond composite layer are chamfered by 0.2 mm, and the transition radius of curvature between the gradient plane 103 and the wing surface 104 and the concave curved surface 109 is 0.8 mm.

[0105] Results: In this embodiment, the PDC composite sheet withstood 39 impact cycles and achieved a ground joint area of ​​7.95 mm after 160 cycles of heavy-duty wet grinding. 2 .

[0106] Example 2

[0107] Methods for preparing diamond composite sheets include:

[0108] 1) By weight percentage, 85% of 12μm synthetic diamond powder, 7% of 4μm synthetic diamond powder, 3% of 1μm synthetic diamond powder and 4% of cobalt powder are mixed to form a working layer mixture.

[0109] 2) By weight percentage, 83% of 50μm synthetic diamond powder, 10% of 8μm synthetic diamond powder, 4% of 2μm synthetic diamond powder and 3% of cobalt powder are mixed to form a transition layer mixture.

[0110] A cemented carbide matrix, a transition layer mixture, and a working layer mixture are sequentially loaded into a mold along the axial direction and sintered at a temperature of 1540℃ and a pressure of 7.8GPa for 0.5 hours to obtain a diamond composite blank. The polycrystalline diamond composite sheet with the following structure is then prepared by machining using existing technology.

[0111] Among them, such as Figures 1-4 As shown, the diamond composite sheet includes a diamond composite layer 101 and a cemented carbide substrate 102. The diamond composite layer includes a transition layer and a working layer. The end face of the working layer has three gradient planes 103. Each gradient plane extends from the edge of the composite layer and converges at the center of the end face. The three gradient planes are evenly distributed circumferentially, that is, the central angle between two adjacent gradient planes is 120°.

[0112] The diamond composite layer has a concave curved surface 109 at the center of its end face. In this embodiment, the edge width of the three gradient planes is 3 mm, the width at the center of the end face is 6 mm, and the angle θ between each gradient plane 103 and the top surface of the cemented carbide substrate 102 is 18°. The radial cross-section of the diamond composite sheet is circular with a diameter of 15.8 mm. The edges of the diamond composite layer are chamfered by 0.2 mm, and the transition radius of curvature between the gradient plane 103 and the wing surface 104 and the concave curved surface 109 is 0.8 mm.

[0113] Results: In this embodiment, the PDC composite sheet withstood 36 impact cycles and had a ground joint area of ​​7.2 mm after 160 cycles of heavy-duty wet grinding. 2 .

[0114] Example 3

[0115] Methods for preparing diamond composite sheets include:

[0116] 1) By weight percentage, 84% of 30μm synthetic diamond powder, 10% of 6μm synthetic diamond powder, 1% of 2μm synthetic diamond powder and 5% of cobalt powder are mixed to form a working layer mixture.

[0117] 2) By weight percentage, 80% of 32μm synthetic diamond powder, 10% of 12μm synthetic diamond powder, 5% of 4μm synthetic diamond powder and 5% of cobalt powder are mixed to form a transition layer mixture.

[0118] A cemented carbide matrix, a transition layer mixture, and a working layer mixture are sequentially loaded into a mold along the axial direction and sintered at a temperature of 1680℃ and a pressure of 8.5GPa for 1 hour to obtain a diamond composite blank. The polycrystalline diamond composite sheet with the following structure is then prepared by machining using existing technology.

[0119] Among them, such as Figures 1-4 As shown, the diamond composite sheet includes a diamond composite layer 101 and a cemented carbide substrate 102. The diamond composite layer includes a transition layer and a working layer. The end face of the working layer has three gradient planes 103. Each gradient plane extends from the edge of the composite layer and converges at the center of the end face. The three gradient planes are evenly distributed circumferentially, that is, the central angle between two adjacent gradient planes is 120°.

[0120] The diamond composite layer has a concave curved surface 109 at the center of its end face. In this embodiment, the edge width of the three gradient planes is 4 mm, the width at the center of the end face is 8 mm, and the angle θ between each gradient plane 103 and the top surface of the cemented carbide substrate 102 is 16°. The radial cross-section of the diamond composite sheet is circular with a diameter of 15.8 mm. The edges of the diamond composite layer are chamfered by 0.2 mm, and the transition curvature radius between the gradient plane 103 and the wing surface 104 and the concave curved surface 109 is 0.8 mm.

[0121] Results: In this embodiment, the PDC composite sheet withstood 35 impact cycles and had a ground joint area of ​​8.7 mm after 160 cycles of heavy-duty wet grinding. 2 .

[0122] Example 4

[0123] Unlike Example 1, a diamond composite sheet with a different structure was prepared according to the formulation of Example 1, but with the same diameter and thickness as Example 1, except that the end face was flat (see Example 1). Figure 5 ), according to the sintering process of Example 1.

[0124] Results: In this embodiment, the PDC composite sheet withstood 30 impact cycles and achieved a ground joint area of ​​9.5 mm after 160 cycles of heavy-duty wet grinding. 2 .

[0125] Example 5

[0126] The difference from Example 1 is that: 1) 82% of 40μm synthetic diamond powder, 10% of 7μm synthetic diamond powder, 3% of 3μm synthetic diamond powder and 5% of cobalt powder are mixed into a working layer mixture by weight percentage.

[0127] 2) By weight percentage, 88% of 55μm synthetic diamond powder, 6% of 10μm synthetic diamond powder, 2% of 6μm synthetic diamond powder and 4% of cobalt powder are mixed to form a transition layer mixture.

[0128] Results: In this embodiment, the PDC composite sheet withstood 27 impact cycles and achieved a ground joint area of ​​10.2 mm after 160 cycles of heavy-duty wet grinding. 2 .

[0129] Comparative Example 1

[0130] Unlike Example 1, the polycrystalline diamond composite sheet with the structure in Example 1 was not prepared using the formulation of Example 1. The formulation of this comparative example is a mixture of 70% 30μm synthetic diamond powder, 20% 10μm synthetic diamond powder, 12% 5μm synthetic diamond powder and 8% cobalt powder to form the working layer mixture.

[0131] The working layer mixture was loaded into a mold and sintered at 1500℃ and 6.5GPa for 1 hour to obtain a diamond composite blank. The polycrystalline diamond composite sheet with the structure of Example 1 was then prepared by processing it using existing technology.

[0132] The PDC composite sheet in this comparative example withstood 28 impact cycles and had a ground joint area of ​​9.2 mm after 160 cycles of heavy-duty wet grinding. 2 .

[0133] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A diamond composite sheet, comprising a cemented carbide substrate (102) and a diamond composite layer (101) disposed on the top surface of the cemented carbide substrate (102), characterized in that, The diamond composite layer (101) includes a working layer for cutting; The working layer material comprises, by weight percentage: 80-85% diamond micropowder of 10-30μm, 5-10% diamond micropowder of 4-6μm, 1-3% diamond micropowder of 1-2μm, and 3-5% of a first binder; the end face of the working layer has at least two protruding gradient planes (103), each of the gradient planes (103) extending from the edge of the working layer and converging at the middle of the end face, the width of the gradient planes (103) gradually increasing from the edge of the composite sheet to the middle of the end face; The diamond composite layer (101) is provided with a heat dissipation surface; the heat dissipation surface is configured as an inwardly concave curved surface (109) located at the center of the diamond composite layer. At least two of the gradient planes (103) are evenly distributed circumferentially, and the angle θ between each of the gradient planes (103) and the top surface of the cemented carbide substrate (102) is 15°~18°. The ratio of the maximum cross-sectional area of ​​the concave curved surface (109) to the cross-sectional area of ​​the diamond composite layer (101) is (1~2):3; Between two adjacent gradient planes (103), a wing surface (104) is provided that gradually slopes downward from the center to the edge, and the transition curvature radius between the wing surface (104) and the gradient plane (103) is 0.6~1mm; The transition radius of curvature between the gradient plane (103) and the concave surface (109) is 0.6~1mm.

2. The diamond composite sheet according to claim 1, characterized in that, The working layer material includes a first binder and diamond micropowder with particle sizes of 10~30μm, 4~6μm and 1~2μm; and / or The diamond composite layer (101) includes a transition layer located between the working layer and the top surface of the cemented carbide substrate; the material of the transition layer includes a second binder and diamond micropowder with particle sizes of 30~60μm, 8~12μm and 2~6μm; and / or The diamond powder includes synthetic diamond powder; and / or The first adhesive and the second adhesive may be the same or different.

3. The diamond composite sheet according to claim 2, characterized in that, The transition layer material comprises, by weight percentage: 80-90% of 30-60μm diamond powder, 5-15% of 8-12μm diamond powder, 1-5% of 2-6μm diamond powder, and 3-5% of a second binder; and / or The first adhesive and the second adhesive comprise cobalt powder.

4. The diamond composite sheet according to claim 2, characterized in that, The transition layer is made of a second binder and diamond micropowder with particle sizes of 30-50 μm, 8-12 μm and 2-4 μm.

5. The diamond composite sheet according to claim 4, characterized in that, The material of the transition layer comprises, by weight percentage: 80-90% of 30-50μm diamond powder, 5-15% of 8-12μm diamond powder, 1-5% of 2-4μm diamond powder, and 3-5% of a second binder.

6. The diamond composite sheet according to claim 1, characterized in that, The ratio of the width of the gradient plane (103) at the edge of the composite sheet to the width at the middle is (1~3):

4.

7. The diamond composite sheet according to claim 1, characterized in that, The width of the gradient plane (103) at the edge of the composite sheet is 2~4mm, and the width of the gradient plane (103) at the middle is 4~8mm.

8. The diamond composite sheet according to any one of claims 1-5, characterized in that, The edges of the diamond composite layer (101) are chamfered; and / or The diamond composite layer (101) is a polycrystalline diamond composite layer; and / or The top surface of the cemented carbide substrate (102) is a concave-convex surface, a flat surface, or a grooved surface; and / or The cross-section of the diamond composite sheet is circular or elliptical.

9. The application of the diamond composite sheet according to any one of claims 1-8 in oil and gas extraction.

10. The application of the diamond composite sheet according to claim 9 in drilling in volcanic rock formations.

11. A method for preparing the diamond composite sheet according to any one of claims 1-8, characterized in that, include: The first binder and diamond micro powder are mixed to obtain a working layer mixture. The working layer mixture and the cemented carbide matrix are then loaded into a mold and sintered to obtain a diamond composite sheet.

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