Diamond compact, and drill bit

Abstract

The present disclosure relates to a diamond compact, comprising: a tooth sleeve, which has an annular cross-section; a blocking disc, which is coaxially fixed to an opening at one end of the tooth sleeve, a tooth lock body being fixed on the inner side of the blocking disc; and a tooth body, which comprises a bearing segment, a base and a tooth crown, wherein the head end surface of the bearing segment is integrally connected to the tail end surface of the base; a lock slot is formed in the tail end surface of the bearing segment, and the tooth crown is fixed to the head end surface of the base; the length of the lock slot is less than the length of the tooth body in the axial direction of the tooth body, such that the lock slot is of a blind hole structure; and the tooth body is mounted within the tooth sleeve, the tooth lock body is axially locked with the lock slot, and the tooth body is rotatable relative to the tooth lock body.

Description

Diamond composite sheets and drill bits

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application 202311863771.9, filed on December 28, 2023, entitled “A Diamond Composite Sheet,” and the entire contents of that disclosure are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the field of drilling tools, and in particular to a diamond composite sheet. Background Art

[0004] Diamond composite sheets are made by sintering diamond micropowder and cemented carbide substrate under ultra-high pressure and high temperature conditions. They have the high hardness, high wear resistance and thermal conductivity of diamond, as well as the strength and impact toughness of cemented carbide. They are ideal materials for manufacturing cutting tools, drilling bits and other wear-resistant tools.

[0005] In the related art, traditional composite sheets are generally cylindrical and are made of a diamond composite layer with a thickness of 2 to 3 mm and a cemented carbide matrix through high temperature and high pressure pressing. They are generally fixedly connected to the PDC drill bit body by brazing or other means.

[0006] When traditional composite blades cut rock, a certain area of ​​the diamond composite layer always contacts and cuts the rock, causing wear of the area of ​​the diamond composite layer, thereby making the diamond composite layer passivated and losing its cutting function. Summary of the Invention

[0007] The present disclosure provides a diamond compact, comprising:

[0008] A gear sleeve, wherein the cross section of the gear sleeve is a circular ring;

[0009] A sealing disc, the sealing disc is coaxially fixed to one end opening of the gear sleeve, and a tooth lock body is fixed on the inner side of the sealing disc;

[0010] The tooth body includes a bearing segment, a base, and a base. The head end face of the bearing segment is connected to the tail end face of the base as a whole. A locking groove is provided on the tail end face of the bearing segment, and a tooth crown is fixed to the head end face of the base. Along the axial direction of the tooth body, the length of the locking groove is less than the length of the tooth body, so that the locking groove is a blind hole structure. The tooth body is installed in the tooth sleeve, the tooth lock body is axially locked with the locking groove, and the tooth body is rotatable relative to the tooth lock body.

[0011] In some embodiments, the tooth lock body comprises:

[0012] a cylinder, one end of which is fixed to the inner side of the occluding disk;

[0013] a frustum, one end of which is fixed to the other end of the cylinder;

[0014] The cylinder and the truncated cone are both provided with grooves, and the grooves penetrate the truncated cone. The cylinder is inserted into the locking groove, and the truncated cone is axially locked with the locking groove.

[0015] In some embodiments, the lock slot comprises:

[0016] a first chamber and a second chamber, wherein the first chamber is in communication with the second chamber, and a diameter of the second chamber is larger than a diameter of the first chamber;

[0017] The cylinder is inserted into the first cavity, and the frustum is axially locked with the second cavity.

[0018] In some embodiments, the locking groove is provided with a first conical opening at one end close to the sealing disk. The first conical opening is coaxially arranged with the first chamber and is interconnected. The diameter of the first conical opening gradually decreases inward.

[0019] In some embodiments, a third chamber and a second chamber are formed at one end of the tooth body, a locking ring is fixed in the third chamber, so that the interior of the locking ring forms a first chamber, the second chamber is coaxially connected to the first chamber and one end is closed, and the diameter of the second chamber is larger than the diameter of the first chamber, so that the first chamber and the second chamber form the stepped locking groove;

[0020] The cylinder is inserted into the first cavity, and the frustum is axially locked in the second cavity.

[0021] In some embodiments, the locking ring has an opening at one end close to the sealing disk, and the second conical opening is coaxial with and adjacent to the first chamber, and the diameter of the second conical opening gradually decreases inward.

[0022] In some embodiments, the groove comprises:

[0023] a first groove, passing through the frustum;

[0024] The second groove is opened in the cylinder, the first groove is connected to the second groove, and the width of the second groove is smaller than the width of the first groove.

[0025] In some embodiments, an annular groove is formed on the inner circumference of the tail end of the gear sleeve, the annular groove is coaxially arranged with the gear sleeve, and the diameter of the annular groove is larger than the diameter of the gear sleeve;

[0026] The sealing disk is arranged in the annular groove and fixed to the gear sleeve.

[0027] In some embodiments, a third tapered opening is formed on the head end surface of the gear sleeve, and the diameter of the third tapered opening gradually decreases inwardly;

[0028] The outer wall of the tooth body is provided with a conical ring, and the conical ring is adapted to the third conical opening.

[0029] In some embodiments, among the various components of the diamond compact, the material of the tooth sleeve is the best in terms of wear resistance and hardness, and the material of the tooth lock body is the best in terms of elasticity and fracture toughness.

[0030] In some embodiments, the diamond compact includes at least one of the following:

[0031] The material of the gear sleeve includes cemented carbide;

[0032] The material of the tooth lock body includes spring steel; and

[0033] The material of the tooth crown includes polycrystalline diamond.

[0034] In some embodiments, the outer peripheral surface of the gear sleeve includes a cylindrical section and a conical section arranged adjacent to each other, the conical section is located at the tail end and tapers outward, and the cone angle of the conical section ranges from 6° to 40°.

[0035] The present disclosure also provides a drill bit including a plurality of diamond compacts mounted on a body thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] FIG1 is a cross-sectional view of a diamond compact according to an embodiment of the present disclosure;

[0038] FIG2 is a schematic structural diagram of the connection between the sealing disk and the tooth lock body of the diamond composite sheet according to an embodiment of the present disclosure;

[0039] FIG3 is a cross-sectional view of a tooth body of a diamond compact according to an embodiment of the present disclosure;

[0040] FIG4 is a cross-sectional view of a diamond compact according to an embodiment of the present disclosure;

[0041] FIG5 is a cross-sectional view of a tooth body of a diamond compact according to an embodiment of the present disclosure;

[0042] FIG6 is a cross-sectional view of a tooth body of a diamond compact according to an embodiment of the present disclosure;

[0043] FIG7 is a cross-sectional view of a tooth sleeve of a diamond compact according to an embodiment of the present disclosure; and

[0044] FIG8 is a cross-sectional view of a tooth sleeve of a diamond compact according to an embodiment of the present disclosure.

[0045] In the figure: 1. Tooth sleeve; 11. Annular groove; 12. Third conical mouth; 2. Sealing disk; 3. Tooth lock body; 31. Groove; 311. First groove; 312. Second groove; 32. Cylinder; 33. Cone; 4. Tooth body; 41. Locking groove; 411. First chamber; 412. Second chamber; 42. First conical mouth; 43. Third chamber; 44. Conical ring; 47. Bearing section; 48. Base; 5. Locking ring; 51. Second conical mouth; 6. Tooth crown; 101. Cylindrical section; 102. Conical section. DETAILED DESCRIPTION

[0046] To help those skilled in the art better understand the present disclosure, the following will provide a clear and complete description of the technical solutions in the embodiments of the present disclosure, in conjunction with the accompanying drawings. It is clear that the described embodiments are only a portion of the embodiments of the present disclosure, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the present disclosure without creative effort are within the scope of protection of the present disclosure.

[0047] In the description of the present disclosure, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0048] It should be noted that, in the present disclosure, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0049] The disclosed embodiments provide a diamond composite sheet, the tooth body of which can rotate around the tooth sleeve. The contact position between the tooth crown and the rock is constantly changing, the wear of the tooth crown at the same position will be reduced, and the probability of sudden fracture of the tooth crown will be greatly reduced. The cutting edge can be kept sharp for a long time, and the service life of the composite sheet can be extended, thereby improving the drilling speed and footage of the PDC drill bit.

[0050] As shown in Figure 1, an embodiment of the present disclosure provides a diamond composite sheet, which may include: a gear sleeve 1, the cross-section of the gear sleeve 1 is arranged in a circular ring; a sealing disk 2, the sealing disk 2 is coaxially fixed to one end opening of the gear sleeve 1, and a tooth lock body 3 is fixed on the inner side of the sealing disk 2; a tooth body 4, including a bearing segment 47, a base 48, and a tooth crown 6, the head end face of the bearing segment 47 and the tail end face of the base 48 are connected as a whole, a locking groove 41 is provided on the tail end face of the bearing segment 47, and a tooth crown 6 is fixed on the head end face of the base 48, along the axial direction of the tooth body 4, the length of the locking groove 41 is less than the length of the tooth body 4, so that the locked groove 14 is a blind hole structure, the tooth body 4 is installed in the gear sleeve 1, the tooth lock body 3 is axially locked with the locking groove 41, and the tooth body 4 can rotate relative to the tooth lock body 3. Since the locking groove 14 is a blind hole structure and does not penetrate the tooth body 4, the weak point at the junction of the bearing section 47 and the base 48 of the tooth body does not produce obvious strength weakening. As a result, the tooth body 4 maintains a relatively high strength and is not prone to breakage when subjected to large working loads.

[0051] During the internal assembly process of the tooth body extending into the tooth sleeve, the tooth lock body 3 will be axially locked with the locking groove 41 of the tooth body 4, so that the tooth body 4 cannot be separated from the tooth lock body 3, and thus the tooth body 4 cannot be pulled out of the tooth sleeve 1, but the tooth body 4 can rotate around the tooth lock body 3 (that is, it can rotate inside the tooth sleeve 1); when the PDC drill bit cuts the tooth, since the tooth body 4 can rotate around the tooth sleeve 1, the contact position of the tooth crown 6 with the rock is constantly changing, the wear of the same position of the tooth crown 6 will be reduced, and the probability of sudden rupture of the tooth crown 6 will be greatly reduced, the cutting edge can be kept sharp for a long time, the service life of the composite piece is extended, and the drilling speed and footage of the PDC drill bit are improved.

[0052] In one embodiment, as shown in Figures 1 and 2 or as shown in Figures 2 and 4, the tooth lock body 3 includes: a cylinder 32, one end of the cylinder 32 is fixed to the inner side of the sealing disk 2; a frustum 33, one end of the frustum 33 is fixed to the other end of the cylinder 32; the cylinder 32 and the frustum 33 are both provided with a groove 31, the groove 31 includes a first groove 311 and a second groove 312 that are connected, the first groove 311 passes through the frustum 33, the second groove 312 is provided in the cylinder 32, and the width of the first groove 311 is greater than the width of the second groove 312, so that the frustum 33 can produce more radial contraction and pass through the locking groove 41 more easily. At the same time, the cylinder 32 can also maintain good strength, the cylinder 32 is inserted into the locking groove 41 and the frustum 33 is axially locked with the locking groove 41. Specifically, as shown in FIG. 2 , the provision of the groove 31 facilitates the tooth lock body 3 to undergo radial extrusion deformation and be inserted into the lock groove 41 , and to be axially locked with the step portion of the lock groove 41 .

[0053] In one embodiment, as shown in FIG3 , the lock slot 41 may include: a first chamber 411 and a second chamber 412, wherein the axes of the first chamber 411 and the second chamber 412 are parallel and interconnected, and the diameter of the second chamber 412 is larger than the diameter of the first chamber 411; the cylinder 32 is inserted into the first chamber 411, and the frustum 33 is axially locked with the second chamber 412. During the insertion of the frustum 33 into the first chamber 411, the frustum 33 undergoes a certain degree of extrusion deformation until the frustum 33 moves into the second chamber 412 and returns to its original shape, while the cylinder 32 is located in the first chamber 411. At this time, the tooth lock body 3 and the lock slot 41 are axially locked and cannot move in the axial direction, but can rotate around the axis.

[0054] Furthermore, as shown in Figures 1 and 3, the lock slot 41 has a first tapered opening 42 at one end near the sealing disk 2, with the diameter of the first tapered opening 42 gradually decreasing inward. The end face of the tooth body 4 inserted into the gear sleeve 1 is the tail end face, while the end face exposed outside the gear sleeve 1 is the head end face. The design of the first tapered opening 42 facilitates the smooth insertion of the tooth lock body 3 into the lock slot 41.

[0055] In one embodiment, as shown in Figures 4, 5, and 6, a third chamber 43 is defined at one end of the tooth body 4. A locking ring 5 is fixed within the third chamber 43, forming a first chamber 411 within the locking ring 5. A second chamber 412 is defined on the inner bottom wall of the first chamber 411. The diameter of the second chamber 412 is greater than that of the first chamber 411, forming a locking groove 41 between the first chamber 411 and the second chamber 412. The cylinder 32 is inserted into the first chamber 411, and the frustum 33 is axially locked with the second chamber 412. The structure of the tooth lock body 3 remains unchanged. Through the cooperation of the third chamber 43 and the locking ring 5, a locking groove 41 (i.e., the first chamber 411 and the second chamber 412) can be formed in the diamond compact. The locking ring 5 can first be assembled with the tooth lock body 3 by clearance fit, and then the locking ring 5 and the third chamber 43 of the tooth body 4 are brazed and fixed, or the locking ring 5 can be assembled with the tooth body 4 by interference fit to form a fixed connecting piece of the tooth body 4-locking ring 5, which is convenient for assembling the fixed connecting piece of the tooth body 4-locking ring 5 with the gear sleeve 1 and the tooth lock body 3.

[0056] Furthermore, as shown in Figure 6, the rear end face of the locking ring 5 is provided with a second tapered opening 51, the diameter of which gradually decreases inward. The end face of the locking ring 5 that is away from the third chamber 43 is the rear end face, while the end face of the locking ring 5 that is inserted into the third chamber 43 is the head end face. The gradually decreasing diameter of the second tapered opening 51 facilitates the smooth introduction of the tooth lock body 3 into the first chamber 411 formed within the locking ring 5, improving assembly efficiency and convenience.

[0057] In one embodiment, as shown in Figure 7, an annular groove 11 is defined on the inner circumference of the rear end face of the gear sleeve 1. The annular groove 11 is coaxial with the gear sleeve 1 and has a diameter greater than that of the gear sleeve 1. The sealing disk 2 is received within the annular groove 11 and secured to the gear sleeve 1. The end face of the gear sleeve 1 facing away from the tooth crown 6 is the rear end face, while the end face closer to the tooth crown 6 is the head end face. The sealing disk 2 and the gear sleeve 1 can be mounted using an interference fit or a clearance fit coupled with brazing.

[0058] In one embodiment, as shown in FIG7 , the head end face of the gear sleeve 1 is provided with a third tapered opening 12, the diameter of which gradually decreases inwardly. An integrally formed conical ring 44 is provided on the outer wall between the head end face and the tail end face of the gear body 4, and the conical ring 44 is adapted to the third tapered opening 12. The third tapered opening 12 facilitates the introduction of the gear body 4 into the interior of the gear sleeve 1 and facilitates subsequent position-limiting connection with the gear lock body 3. The conical ring 44 can contact the third tapered opening 12 of the gear sleeve 1, thereby increasing the load-bearing capacity of the diamond compact.

[0059] In one embodiment, among the various components of the diamond composite sheet, the materials of the tooth sleeve 1 and the tooth body 4 are the best in terms of wear resistance and hardness, and the material of the tooth lock body 3 is the best in terms of elasticity and fracture toughness. For example, the materials of the tooth sleeve 1 and the tooth body 4 can both include cemented carbide; the material of the tooth lock body 3 can include spring steel, and the material of the tooth crown 6 can include polycrystalline diamond. This satisfies the following requirements: when the diamond composite sheet is assembled, the tooth lock body 3 can withstand the large deformation and high stress generated by passing through the first chamber, and when the diamond composite sheet is cutting rock, the tooth lock body 3 can withstand the greater impact force and impact deformation generated at the moment of collision without being prone to fracture; at the same time, when rotating to cut rock, relative rotation will occur between the tooth sleeve 1 and the tooth body 4, and rock particles entering between the tooth sleeve 1 and the tooth body 4 will cause particle wear. Due to the good wear resistance and hardness of the tooth sleeve 1 and the tooth body 4, the wear resistance remains excellent.

[0060] In one embodiment, the tooth sleeve 4 includes a cylindrical section 101 and a conical section 102 arranged adjacent to each other. The conical section 102 is located at the tail end and tapers outward, and the taper angle of the outer wall of the conical section ranges from 6° to 40°. By reducing the size of the conical section 102 at the tail end, compared to the tooth sleeve 4 having an overall cylindrical structure, when the tail ends of multiple diamond composite sheets are installed to the drill bit at intervals by welding, the distance between the tail ends of the multiple diamond composite sheets will be greater. In other words, the drill bit body material between two adjacent diamond composite sheets will be thicker and less likely to be penetrated during the welding process, thereby reducing defects caused by welding.

[0061] In one embodiment, as shown in Figure 1, the tooth body 4 can be a stepped cylinder with a large outer diameter of the base 48 and a small outer diameter of the bearing section 47. The tail end face of the bearing section 47 (that is, the tail end face of the tooth body 4) is provided with a locking groove 41, and the head end face of the base 48 (that is, the head end face of the tooth body 4) is fixed with a tooth crown 6.

[0062] In the above embodiment, the difference between the diameter of the wider end of the cone 33 and the diameter of the first chamber 411 can be in the range of 0.1mm to 3.0mm; the difference between the diameter of the wider end of the cone 33 and the diameter of the second chamber 412 can be in the range of -0.1mm to -2.0mm.

[0063] In the above embodiments, the first chamber 411 , the second chamber 412 and the third chamber 43 may be cylindrical grooves or conical grooves.

[0064] The foregoing description is intended only to provide specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not to be limited to the embodiments shown herein, but is to be construed in the broadest manner consistent with the principles and novel features claimed herein.

Claims

1. A diamond composite sheet, comprising: A tooth sleeve (1), the cross-section of the tooth sleeve (1) being circular; A plugging disc (2), the plugging disc (2) being coaxially fixed to one end opening of the tooth sleeve (1), and a tooth locking body (3) being fixed inside the plugging disc (2); A tooth body (4), including a bearing section (47), a base (48), and a tooth crown (6). The head end face of the bearing section (47) is integrally connected to the tail end face of the base (48). A locking groove (41) is provided on the tail end face of the bearing section (47), and a tooth crown (6) is fixed to the head end face of the base (48). Along the axial direction of the tooth body (4), the length of the locking groove (41) is less than the length of the tooth body (4), such that the locking groove (14) is a blind hole structure. The tooth body (4) is installed inside the tooth sleeve (1), the tooth locking body (3) is axially locked with the locking groove (41), and the tooth body (4) is rotatable relative to the tooth locking body (3).

2. The diamond composite sheet according to claim 1, wherein the tooth locking body (3) comprises: A cylinder (32), one end of the cylinder (32) being fixed inside the plugging disc (2); A frustum (33), one end of the frustum (33) being fixed to the other end of the cylinder (32); Both the cylinder (32) and the frustum (33) are provided with grooves (31), and the grooves (31) penetrate through to the frustum (33). The cylinder (32) is inserted into the locking groove (41), and the frustum (33) is axially locked with the locking groove (41).

3. The diamond composite sheet according to claim 2, wherein the locking groove (41) comprises: A first chamber (411) and a second chamber (412), the first chamber (411) being in communication with the second chamber (412), and the diameter of the second chamber (412) being larger than the diameter of the first chamber (411); The cylinder (32) is inserted into the first chamber (411), and the frustum (33) is axially locked with the second chamber (412).

4. The diamond composite sheet according to claim 3, wherein a first tapered opening (42) is provided at the opening of one end of the locking groove (41) close to the plugging disc (2). The first tapered opening (42) is coaxially arranged with and in communication with the first chamber (411), and the diameter of the first tapered opening (42) gradually decreases inward.

5. The diamond composite sheet according to any one of claims 2-4, wherein a third chamber (43) and a second chamber (412) are formed at one end of the tooth body (4), a locking ring (5) is fixed in the third chamber (43), a first chamber (411) is formed inside the locking ring (5), the second chamber (412) is coaxially communicated with the first chamber (411) and one end thereof is closed, and the diameter of the second chamber (412) is larger than that of the first chamber (411), so that the first chamber (411) and the second chamber (412) form the stepped lock groove (41); the cylinder (32) is inserted into the first chamber (411), and the frustum (33) is axially locked in the second chamber (412).

6. The diamond composite sheet according to claim 5, wherein a second tapered opening (51) is formed at the opening at one end of the locking ring (5) close to the plugging disc (2), the second tapered opening (51) is coaxially and adjacently arranged with the first chamber (411), and the diameter of the second tapered opening (51) gradually decreases inward.

7. The diamond composite sheet according to any one of claims 2-6, wherein the groove (31) includes: a first groove (311) penetrating through the frustum (33); a second groove (312) formed in the cylinder (32), the first groove (311) is communicated with the second groove (312), and the width of the second groove (312) is smaller than that of the first groove (311).

8. The diamond composite sheet according to any one of claims 1-7, wherein an annular groove (11) is formed on the inner peripheral surface of the tail end of the tooth sleeve (1), the annular groove (11) is coaxially arranged with the tooth sleeve (1), and the diameter of the annular groove (11) is larger than that of the tooth sleeve (1); the plugging disc (2) is arranged in the annular groove (11) and fixed to the tooth sleeve (1).

9. The diamond composite sheet according to any one of claims 1-8, wherein a third tapered opening (12) is formed on the head end face of the tooth sleeve (1), and the diameter of the third tapered opening (12) gradually decreases inward; a conical ring (44) is arranged on the outer wall of the tooth body (4), and the conical ring (44) is adapted to the third tapered opening (12).

10. The diamond composite sheet according to any one of claims 1-9, wherein among the components of the diamond composite sheet, the materials of the tooth sleeve (1) and the tooth body (4) are the best in terms of wear resistance and hardness, and the material of the tooth lock body (3) is the best in terms of elasticity and fracture toughness.

11. The diamond composite sheet according to claim 10, comprising at least one of the following: the materials of the tooth sleeve (1) and the tooth body (4) include cemented carbide; the material of the tooth lock body (3) includes spring steel; and the material of the tooth crown (6) includes polycrystalline diamond.

12. The diamond composite sheet according to claim 5 or 6, wherein the outer peripheral surface of the tooth sleeve (1) includes an adjacent cylindrical section (101) and a conical section (102), the conical section (102) is located at the tail end and tapers outward, and the cone angle of the conical section (102) ranges from 6° to 40°.

13. A drill bit, comprising a plurality of diamond composite sheets according to any one of claims 1-12 mounted on its body.

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