Polycrystalline diamond compact with stable structure

Abstract

The utility model relates to the field of production and manufacturing of polycrystalline diamond compacts, in particular to a polycrystalline diamond compact with a stable structure, which is cylindrical and is characterized in that the polycrystalline diamond compact is provided with a plurality of grooves; the cylinder is composed of a cobalt-removed polycrystalline diamond layer, a transition polycrystalline diamond layer and a hard alloy matrix layer which are sequentially compounded from top to bottom, the transition polycrystalline diamond layer is combined between the cobalt-removed polycrystalline diamond layer and the hard alloy matrix layer in a stacked mode, and protrusions are arranged on the upper surface of the hard alloy matrix layer. The lower surface of the transition diamond layer is provided with indents matched with the bulges on the upper surface of the hard alloy matrix layer; the upper surface of the transition polycrystalline diamond layer is provided with protrusions, and the lower surface of the cobalt-removed polycrystalline diamond layer is provided with indents matched with the protrusions on the upper surface of the transition polycrystalline diamond layer. The purpose of reducing the interface stress of the polycrystalline diamond layer and the hard alloy layer is achieved.

Description

Technical Field

[0001] This utility model relates to the field of polycrystalline diamond composite sheet production and manufacturing, and more specifically, to a polycrystalline diamond composite sheet with a stable structure. Background Technology

[0002] Polycrystalline diamond composite (PDC) sheets are made by sintering diamond micropowder with cemented carbide (WC-Co) matrix under high temperature and high pressure. As a composite material, it has both the high hardness, high wear resistance and thermal conductivity of diamond and the impact toughness of cemented carbide, making it an ideal material for manufacturing cutting tools, drilling bits and other wear-resistant tools.

[0003] With market development, the expansion of drilling areas, increasingly complex drilling formations, and more demanding drilling conditions, customers have higher and higher requirements for the impact toughness and stability of products. Improving the impact toughness and stability of products has always been the goal of industry professionals.

[0004] High-end polycrystalline diamond composite (PDC) sheets, as composite materials, are mainly composed of diamond micron powder (thermal expansion coefficient approximately 0.8 × 10⁻⁶ / K), tungsten carbide (thermal expansion coefficient approximately 4.5 × 10⁻⁶ / K), and cobalt (thermal expansion coefficient approximately 13.3 × 10⁻⁶ / K). They consist of a cobalt-free diamond layer (pure diamond layer), a diamond layer (diamond and cobalt), and a cemented carbide matrix (WC-Co). The difference in thermal expansion coefficients between the cobalt-free diamond layer, the diamond layer, and the cemented carbide matrix leads to variations in thermal expansion coefficients during actual drilling processes. Polycrystalline diamond composite sheets gradually release stress under force and heat. Failure phenomena such as surface chipping and delamination will occur at the stress concentration points. The stress concentration points are mainly at the junction of the decobalt-free and non-decobalt-free layers of the diamond layer and the junction of the diamond layer and cemented carbide. On the other hand, although the presence of tungsten carbide and cobalt in the diamond layer will reduce the wear resistance and thermal stability of the product, cobalt is indispensable as a catalyst and binder for diamond growth, and at the same time improves the impact toughness of the product. Therefore, how to make reasonable use of these components to improve product quality becomes very important.

[0005] In order to ensure both the impact toughness and stability of polycrystalline diamond composite sheets and improve their wear resistance, a polycrystalline diamond composite sheet with a stable structure was designed. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a polycrystalline diamond composite sheet with a stable structure, which not only ensures the impact toughness and stability of the polycrystalline diamond composite sheet, but also improves its wear resistance.

[0007] The technical solution of this utility model is as follows:

[0008] A stable polycrystalline diamond composite sheet is disclosed. The polycrystalline diamond composite sheet is cylindrical, and the cylindrical shape consists of, from top to bottom, a cobalt-free polycrystalline diamond layer 1, a transition polycrystalline diamond layer 2, and a cemented carbide substrate layer 3, which are sequentially laminated. The transition polycrystalline diamond layer 2 is stacked between the cobalt-free polycrystalline diamond layer 1 and the cemented carbide substrate layer 3. The upper surface of the cemented carbide substrate layer 3 has protrusions, and the lower surface of the transition diamond layer 2 has concave areas that correspond to the protrusions on the upper surface of the cemented carbide substrate layer 3. The upper surface of the transition polycrystalline diamond layer 2 has protrusions, and the lower surface of the cobalt-free polycrystalline diamond layer 1 has concave areas that correspond to the protrusions on the upper surface of the transition polycrystalline diamond layer 2.

[0009] The upper surface of the cemented carbide substrate layer 3 has a raised portion called a first flat-top boss 301, the periphery of which transitions from an arc to a first ring 302. The lower surface of the transition polycrystalline diamond layer 2 mates with the upper surface of the cemented carbide substrate layer 3. The upper surface of the transition polycrystalline diamond layer 2 has a raised portion called a second flat-top boss 201, the periphery of which transitions from an arc to a second ring 202. The lower surface of the decobaltized polycrystalline diamond layer 1 mates with the upper surface of the transition polycrystalline diamond layer 2.

[0010] The arc transition around the first flat-top boss 301 or the second flat-top boss 201 is a concave arc transition.

[0011] The upper edge of the circular arc transition around the first flat-top boss 301 or the second flat-top boss 201 is a convex circular arc connecting to the lower edge a concave circular arc transition.

[0012] The plane diameter of the first flat-top boss 301 or the second flat-top boss 201 is 85-95% of the diameter of the polycrystalline diamond composite sheet. The height difference between the first flat-top boss 301 and the first ring 302, and the height difference between the second flat-top boss 201 and the second ring 202 are both 0.5-1.5mm.

[0013] The transition polycrystalline diamond layer 2 includes a wear-resistant polycrystalline diamond layer 21 and an impact-resistant polycrystalline diamond layer 22. The wear-resistant polycrystalline diamond layer 21 is closer to the cobalt-free diamond layer 1, and the impact-resistant polycrystalline diamond layer 22 is closer to the cemented carbide matrix layer 3. The upper surface of the impact-resistant diamond layer 22 has protrusions, and the lower surface of the wear-resistant polycrystalline diamond layer 21 has concave areas that correspond to the protrusions on the upper surface of the impact-resistant polycrystalline diamond layer 22.

[0014] The cobalt-free polycrystalline diamond layer 1 is composed of diamond micro powder with a particle size of 12-20 μm, the wear-resistant polycrystalline diamond layer 21 is composed of diamond micro powder with a particle size of 20-30 μm, and the impact-resistant polycrystalline diamond layer 22 is composed of diamond micro powder with a particle size of 30-50 μm.

[0015] The composition of the cobalt-free polycrystalline diamond layer 1 is: diamond micro powder accounts for 100% by weight; the composition of the wear-resistant polycrystalline diamond layer 21 is: diamond micro powder accounts for 92-99% by weight, tungsten carbide accounts for 0-5% by weight, and cobalt accounts for 1-3% by weight; the composition of the impact-resistant polycrystalline diamond layer 22 is: diamond micro powder accounts for 85-99% by weight, tungsten carbide accounts for 0-10% by weight, and cobalt accounts for 1-5% by weight; and the composition of the cemented carbide matrix layer 3 is: tungsten carbide accounts for 85-95% by weight and cobalt accounts for 5-15% by weight.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] This invention provides a stable polycrystalline diamond composite sheet. By gradient distribution of tungsten carbide and cobalt in the overall polycrystalline diamond composite sheet, adjusting the particle size of diamond in the composite layer, and changing the assembly shape of the composite layer, the thermal expansion difference between diamond micro powder layers and between cemented carbide and diamond micro powder layers is reduced, thereby improving the overall impact toughness and stability of the product and enhancing the wear resistance of the polycrystalline diamond composite sheet. Attached Figure Description

[0018] Figure 1 This is a cross-sectional structural diagram of the first embodiment of the polycrystalline diamond composite sheet of this utility model.

[0019] Figure 2 This is a cross-sectional structural diagram of the second embodiment of the polycrystalline diamond composite sheet of this utility model.

[0020] Among them, 1 is a cobalt-free polycrystalline diamond layer; 2 is a transition polycrystalline diamond layer; 21 is a wear-resistant polycrystalline diamond layer; 22 is an impact-resistant polycrystalline diamond layer; 201 is a second flat-top boss; 202 is a second ring; 3 is a cemented carbide substrate layer; 301 is a first flat-top boss; 302 is a first ring. Detailed Implementation

[0021] This invention provides a polycrystalline diamond composite sheet with a stable structure. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following provides a more detailed description. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this invention.

[0022] See Figure 1 , Figure 1This is a cross-sectional structural diagram of the first embodiment of the polycrystalline diamond composite sheet of this utility model. The utility model provides a stable polycrystalline diamond composite sheet, which is cylindrical. From top to bottom, the cylindrical sheet consists of a cobalt-free polycrystalline diamond layer 1, a transition polycrystalline diamond layer 2, and a cemented carbide substrate layer 3, stacked sequentially. The transition polycrystalline diamond layer 2 is layered between the cobalt-free polycrystalline diamond layer 1 and the cemented carbide substrate layer 3. The upper surface of the cemented carbide substrate layer 3 has protrusions, and the lower surface of the transition diamond layer 2 has concave areas that correspond to the protrusions on the upper surface of the cemented carbide substrate layer 3. Similarly, the upper surface of the transition polycrystalline diamond layer 2 has protrusions, and the lower surface of the cobalt-free polycrystalline diamond layer 1 has concave areas that correspond to the protrusions on the upper surface of the transition polycrystalline diamond layer 2. By adding a transition layer, stress concentration caused by direct bonding between the cobalt-free diamond layer and the cemented carbide substrate layer is avoided, thereby reducing the possibility of the cobalt-free diamond layer detaching during product use.

[0023] The upper surface of the cemented carbide substrate layer 3 has a raised portion called a first flat-topped boss 301. The periphery of the first flat-topped boss 301 transitions from an arc to a first circular ring 302. The lower surface of the transition polycrystalline diamond layer 2 mates with the upper surface of the cemented carbide substrate layer 3. The raised portion of the upper surface of the transition polycrystalline diamond layer 2 is a second flat-topped boss 201. The periphery of the second flat-topped boss 201 transitions from an arc to a second circular ring 202. The lower surface of the decobaltized polycrystalline diamond layer 1 mates with the upper surface of the transition polycrystalline diamond layer 2. The arc transition around the first flat-topped boss 301 or the second flat-topped boss 201 is a concave arc transition. The interlayer interface adopts a concave-convex form to reduce the interfacial stress between the polycrystalline diamond layer and the cemented carbide layer. This not only ensures that excessive cobalt loss does not affect the impact toughness of the product, but also significantly improves the wear resistance and thermal stability of the grinding part during drilling by increasing the decobaltized area on the outer edge of the interlayer interface, thereby increasing the drilling footage.

[0024] The plane diameter of the first flat-top boss 301 or the second flat-top boss 201 is 85-95% of the diameter of the polycrystalline diamond composite sheet. The height difference between the first flat-top boss 301 and the first ring 302, and the height difference between the second flat-top boss 201 and the second ring 202 are both 0.5-1.5mm.

[0025] The transition polycrystalline diamond layer 2 includes a wear-resistant polycrystalline diamond layer 21 and an impact-resistant polycrystalline diamond layer 22. The wear-resistant polycrystalline diamond layer 21 is closer to the cobalt-free diamond layer 1, and the impact-resistant polycrystalline diamond layer 22 is closer to the cemented carbide matrix layer 3. The upper surface of the impact-resistant diamond layer 22 has protrusions, and the lower surface of the wear-resistant polycrystalline diamond layer 21 has concave areas that match the protrusions on the upper surface of the impact-resistant polycrystalline diamond layer 22.

[0026] The cobalt-free polycrystalline diamond layer 1 is composed of diamond micro powder with a particle size of 12-20 μm, the wear-resistant polycrystalline diamond layer 21 is composed of diamond micro powder with a particle size of 20-30 μm, and the impact-resistant polycrystalline diamond layer 22 is composed of diamond micro powder with a particle size of 30-50 μm. By adjusting the particle size of the diamond micro powder in the composite layer, the average particle size of the diamond micro powder gradually increases from top to bottom, which can significantly improve the impact toughness of the product.

[0027] The composition of the cobalt-free polycrystalline diamond layer 1 is: diamond micro powder accounts for 100% by weight; the composition of the wear-resistant polycrystalline diamond layer 21 is: diamond micro powder accounts for 92-99% by weight, tungsten carbide accounts for 0-5% by weight, and cobalt accounts for 1-3% by weight; the composition of the impact-resistant polycrystalline diamond layer 22 is: diamond micro powder accounts for 85-99% by weight, tungsten carbide accounts for 0-10% by weight, and cobalt accounts for 1-5% by weight; and the composition of the cemented carbide matrix layer 3 is: tungsten carbide accounts for 85-95% by weight and cobalt accounts for 5-15% by weight. Among them, from top to bottom, the content of tungsten carbide and cobalt in the diamond layer gradually increases from 0 and does not exceed that in the cemented carbide matrix layer. This reduces the difference in thermal expansion between the composite materials and avoids product delamination caused by significant stress concentration.

[0028] See Figure 2 , Figure 2 This is a cross-sectional structural diagram of the second embodiment of the polycrystalline diamond composite sheet of this utility model. Unlike the first embodiment, the upper edge of the arc transition around the first flat-top boss 301 or the second flat-top boss 201 is a convex arc connecting to the lower edge a concave arc transition, in order to reduce the interfacial stress between the polycrystalline diamond layer and the cemented carbide layer.

[0029] In summary, this utility model provides a stable polycrystalline diamond composite sheet. (1) By gradient distribution of tungsten carbide and cobalt in the overall polycrystalline diamond composite sheet, the content of tungsten carbide and cobalt in the diamond layer gradually increases from 0 and is not higher than that in the cemented carbide matrix layer, reducing the thermal expansion difference between composite materials and avoiding product delamination caused by significant stress concentration. (2) By adjusting the particle size of diamond in the composite layer, the average particle size of diamond micro powder gradually increases from top to bottom, which can significantly improve the impact toughness of the product. (3) By changing the assembly shape of the composite layer, the interlayer interface adopts a concave-convex form, which can not only ensure that excessive cobalt loss affects the impact toughness of the product, but also significantly improve the wear resistance and thermal stability of the grinding part of the product during drilling by increasing the cobalt removal area on the outer edge of the interlayer interface, and increase the drilling footage. Through the above optimization, the thermal expansion difference between diamond micro powder layers and between cemented carbide and diamond micro powder layers is reduced, improving the overall impact toughness and stability of the product, and improving the wear resistance of the polycrystalline diamond composite sheet.

[0030] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A stable polycrystalline diamond composite sheet, wherein the polycrystalline diamond composite sheet is cylindrical, characterized in that, The cylindrical shape consists of a cobalt-free polycrystalline diamond layer (1), a transition polycrystalline diamond layer (2), and a cemented carbide substrate layer (3) stacked from top to bottom. The transition polycrystalline diamond layer (2) is stacked between the cobalt-free polycrystalline diamond layer (1) and the cemented carbide substrate layer (3). The upper surface of the cemented carbide substrate layer (3) has a protrusion, and the lower surface of the transition polycrystalline diamond layer (2) has a concave shape that matches the protrusion on the upper surface of the cemented carbide substrate layer (3). The upper surface of the transition polycrystalline diamond layer (2) has a protrusion, and the lower surface of the cobalt-free polycrystalline diamond layer (1) has a concave shape that matches the protrusion on the upper surface of the transition polycrystalline diamond layer (2).

2. The polycrystalline diamond composite sheet with a stable structure as described in claim 1, characterized in that, The upper surface of the cemented carbide substrate layer (3) has a raised portion called a first flat-top boss (301). The periphery of the first flat-top boss (301) is transitioned from an arc to a first ring (302). The lower surface of the transition polycrystalline diamond layer (2) is in contact with the upper surface of the cemented carbide substrate layer (3). The upper surface of the transition polycrystalline diamond layer (2) has a raised portion called a second flat-top boss (201). The periphery of the second flat-top boss (201) is transitioned from an arc to a second ring (202). The lower surface of the decobaltized polycrystalline diamond layer (1) is in contact with the upper surface of the transition polycrystalline diamond layer (2).

3. The polycrystalline diamond composite sheet with a stable structure as described in claim 2, characterized in that, The arc transition around the first flat-top boss (301) or the second flat-top boss (201) is a concave arc transition.

4. The polycrystalline diamond composite sheet with a stable structure as described in claim 2, characterized in that, The upper edge of the circular arc transition around the first flat-top boss (301) or the second flat-top boss (201) is a convex circular arc connecting to the lower edge concave circular arc transition.

5. The polycrystalline diamond composite sheet with a stable structure as described in claim 3, characterized in that, The plane diameter of the first flat-top boss (301) or the second flat-top boss (201) is 85-95% of the diameter of the polycrystalline diamond composite sheet. The height difference between the first flat-top boss (301) and the first ring (302) and the height difference between the second flat-top boss (201) and the second ring (202) are both 0.5-1.5mm.

6. The polycrystalline diamond composite sheet with a stable structure as described in claim 5, characterized in that, The transition polycrystalline diamond layer (2) includes a wear-resistant polycrystalline diamond layer (21) and an impact-resistant polycrystalline diamond layer (22). The wear-resistant polycrystalline diamond layer (21) is closer to the decobalt-free polycrystalline diamond layer (1), and the impact-resistant polycrystalline diamond layer (22) is closer to the cemented carbide matrix layer (3). The upper surface of the impact-resistant polycrystalline diamond layer (22) has a protrusion, and the lower surface of the wear-resistant polycrystalline diamond layer (21) has an indentation that matches the protrusion on the upper surface of the impact-resistant polycrystalline diamond layer (22).

7. The polycrystalline diamond composite sheet with a stable structure as described in claim 6, characterized in that, The cobalt-free polycrystalline diamond layer (1) is composed of diamond micro powder with a particle size of 12-20 μm, the wear-resistant polycrystalline diamond layer (21) is composed of diamond micro powder with a particle size of 20-30 μm, and the impact-resistant polycrystalline diamond layer (22) is composed of diamond micro powder with a particle size of 30-50 μm.

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