RU2320615C2 - Cutting member compacted in tablet - Google Patents

Abstract

FIELD: production of cutting members compacted in tablets.

SUBSTANCE: proposed cutting member compacted in tablet includes many diamonds or diamond-like elements which are partially bonded forming body of continuous diamond matrix and substrate containing catalyzing material. Inter-crystalline zones located in between diamond crystals form continuous inter-crystalline matrix containing catalyzing material. Diamond matrix body has working surface; part of inter-crystalline matrix body located in the immediate vicinity of working surface is free from catalyzing material at considerable degree and forms second inter-crystalline zone; remaining part of inter-crystalline matrix forming the first inter-crystalline zone contains catalyzing material. Average thickness of first inter-crystalline zone does not exceed 0.15 mm.

EFFECT: enhanced wear resistance of cutting members with no loss of impact viscosity.

11 cl, 25 dwg

Description

1. The technical field of the invention

The present invention relates to elements made of a material with a superhard surface, operating under conditions of friction, cutting, drawing, where technical superhard surfaces are required. In particular, the present invention relates to elements of polycrystalline diamonds and polycrystalline diamond-like elements (hereinafter referred to as PKA) with increased wear resistance, and methods for their manufacture.

2. Description of analogues

Polycrystalline diamond elements and polycrystalline diamond-like elements are referred to herein as PKA elements. PKA elements are made of carbon-based materials with extremely short interatomic distances. One type of polycrystalline diamond-like material is known as carbonitride, as described in US Pat. No. 5776615. In general, PKA elements are made from a mixture of materials processed at high temperatures and under high pressure to produce a polycrystalline matrix of interconnected carbon-based superhard crystals. A common feature of PKA elements is the use of catalyzing materials in the process of their formation, the remains of which often impose a limitation on the maximum allowable working temperature of the element.

Known PCA element, made in the form of a two-layer or multilayer PKA element with an outer plate of polycrystalline diamond, which is integral with a substrate made of less solid material, for example, tungsten carbide. The PKA element can be in the form of a round or semicircular tablet, or have another shape that is suitable for the respective application, for example, for use as crimp, radiator, plain bearings, surfaces of pipe fittings, indenters, tool holders, etc. PKA elements of this type can be used in almost any field where a solid wear-resistant and erosion-resistant material is required. The substrate of the PCA element can be soldered to a carrier, often made of sintered tungsten carbide. This is usually done if the PKA is used as a cutting element, for example, as rock cutting heads with fixed or cone cutters installed in the socket of the drill bit, or fixed in the tool holder of the processing machine. These PKA elements are commonly called polycrystalline diamond cutters (PAIRs).

There are many ways to make these PAR elements. For example, in the manufacture of diamond particles can be used with medium sizes of different ranges, which improves wear resistance, as shown in US patent No. 4861350, 5468268 and 5545748, which are given in this case as a reference. In addition, in US patent No. 5135061 and 5607024, which are also given in this case as a reference, describes methods for providing a range of wear resistance on the working surface of the steam. However, due to the fact that when the average size of diamond particles changes, the wear resistance changes, there is a compromise between toughness and wear resistance. Consequently, SAR elements with high wear resistance have a low toughness, which is often unacceptable for SARs used in drilling.

Typically, at higher bulk densities of diamonds in a diamond tablet, wear resistance increases due to toughness. However, in modern PAR elements between a diamond tablet and a substrate, interfaces of complex geometry, as well as other structural solutions, are often often used, which increases the toughness. Although this allows maximum durability and toughness to be maximized at the same time, a compromise still exists and has not changed over the past few years.

Another type of PKA-element is a single PKA-element without a substrate being performed along with it, when the polycrystalline diamond plate is attached to the tool or wear surface using mechanical devices or microwelding. These PKA elements differ from those described above in that the diamond particles are distributed throughout the element. These PKA elements can be held mechanically in place, inserted into a larger PKA element with a substrate, or in another embodiment, they can be made with a metal layer that is attached by soldering or welding. Many PKA elements can be made from one PKA, as shown, for example, in US Pat. Nos. 4,481,016 and 4,525,179, which are hereby incorporated by reference.

PKA elements are most often made by sintering diamond powder with a suitable binder-catalyzing material under high pressure and at high temperature. US Pat. No. 3,141,746, which is incorporated herein by reference, describes one suitable method for producing such a polycrystalline diamond. In accordance with one manufacturing technique for PKA elements, diamond powder is applied to the surface of a preformed tungsten carbide substrate containing cobalt. Then this assembly is exposed to ultra-high temperature and pressure in the press. During this process, cobalt migrates from the substrate to the diamond layer and acts as a binder-catalyzing material, ensuring the bonding of diamond particles with each other, as well as the connection of the diamond layer with the substrate.

The finished PKA element has at least one matrix of diamond crystals bonded to each other via a plurality of intergranular zones containing a binder-catalyzing metal, as described above. Diamond crystals constitute the first continuous diamond matrix, and intergranular zones form a second continuous intergranular matrix containing a binder-catalyzing material. In addition, there are necessarily small zones containing a binder-catalytic material in which diamond growth occurs. These islands are not an integral part of a continuous intergranular matrix consisting of a binder-catalyzing material.

Typically, the bulk density of diamond elements is 85-95%, and the binder-catalyzing element is the remaining 5-15%. Such an element can undergo thermal degradation, which begins at temperatures of approximately 400 ° C, as a result of different thermal expansion of the binder-catalyzing intergranular cobalt and diamond matrix. After sufficient expansion, the bond between the diamonds may be broken, and cracking and chips may occur.

In addition, the presence of a binder-catalyzing material in the intercrystalline zone of a polycrystalline diamond near diamond crystals of a diamond matrix leads to another type of thermal degradation. This presence of a binder-catalyzing material causes graphitization of the diamond as the temperature rises, which usually leads to a limitation of the operating temperature within approximately 750 ° C.

Although cobalt is most often used as a binder-catalyzing material, nevertheless, any element of group VIII can be used for this purpose, including cobalt, nickel, iron, and alloys thereof.

In accordance with US Pat. No. 4,224,380, which is incorporated herein by reference, in order to reduce the thermal degradation of cutting and / or wear-resistant elements, so-called "thermally stable" components were made, which were PCA elements compressed from tablets into polycrystalline diamond . In one type of thermally stable PCA element, after cobalt or other binder-catalyzing material is leached from a continuous intercrystalline matrix of a conventional polycrystalline diamond. Numerous methods are known for leaching a binder-catalyzing material. In US patent No. 4572722 and 4797241, which are given in this case by reference, some methods of leaching are described.

When the binder-catalyzing material is leached, the heat resistance of diamond can increase to approximately 1200 ° C; when the leached, the sintered carbide substrate is also removed. In addition, due to the lack of a solid substrate or other surface capable of forming bonds, there are great difficulties with the installation of such a material.

Methods of manufacturing such a “thermally stable" PKA element typically involve the manufacture of diamonds of relatively low density, of the order of 80% or less. Such a low density of diamond provides complete leaching, but the resulting finished element usually has a relatively low impact strength. Low bulk density is usually achieved by mixing and using relatively small diamond crystals with an average particle size of about 15 microns or less. Typically, these small particles are coated with a catalyst material prior to processing. The mixing process ensures the presence of large distances between the diamond particles in the finished product, while a relatively small fraction of their outer surface is devoted to the formation of bonds between diamonds, which is often less than 50%, which contributes to low impact strength.

In these so-called "thermally stable" polycrystalline diamond components, the absence of a suitable substrate, which provides the formation of bonds for subsequent attachment to the working tool, is solved in several ways. One such method of attaching a substrate to a “thermally stable" polycrystalline diamond tablet is described in US Pat. No. 4,944,772, which is hereby incorporated by reference. In accordance with this technology, a porous polycrystalline diamond tablet is first made, and then it is re-sintered in the presence of a catalytic material at high temperatures and under high pressures with a blocking layer of another material that prevents re-infiltration of the catalytic material through a porous polycrystalline diamond tablet. The resulting product usually has a sharp transition between the compressed tablet and the locking layer, which creates problems caused by stress concentrations during operation.

In US patent No. 4871377 and 5127923, which are given in this case by reference, other similar technologies are proposed to attach the substrate to the "thermally stable" polycrystalline diamond components. Obviously, the weakness of all these technologies is the weakening of bonds between diamonds in a compressed tablet made of polycrystalline diamond as a result of high temperature and high pressure during repeated sintering. It is understood that this breaking / breaking of bonds usually also reduces the toughness of the finished product to an unacceptably low level, which is lower than that of a compressed tablet.

In another form of thermally stable polycrystalline diamond, silicon is used as a catalytic material. The process of making polycrystalline diamond with silicon as a catalytic material is similar to the process described above, with the only exception that at sintering temperatures and pressures, most of the silicon reacts to form silicon carbide, which is not an effective catalytic material. Moreover, the thermal stability of such an element is somewhat higher, but thermal degradation still occurs, since there are silicon residues, which are usually evenly distributed in the intergranular matrix. Again, this type of PCA element causes mounting problems, since there is no surface with which it is possible to form a connection.

More recently, another type of PKA has appeared, in which, when sintering a diamond powder, carbonates, for example, powdered carbonates Mg, Ca, Sr, and Ba, are used as a binder-catalyzing material. PKAs of this type usually have higher wear resistance and hardness than previous types of PKA-elements. However, the mass production of this material is difficult due to the fact that its sintering requires a higher pressure than that used in the sintering of conventional and thermally stable polycrystalline diamond. One of the results of this method is that the body of the polycrystalline diamond obtained in this way is smaller than the elements of ordinary polycrystalline diamonds. Again, thermal degradation may occur in the intergranular matrix due to residues of the binder-catalyzing material. And again, since there is no solid substrate or other surface with which it is possible to form a joint, there are great difficulties with the installation of such material on the working surface.

Due to the low toughness, attempts to connect thermally stable PKAs with mounting systems in order to use their increased temperature stability were not as successful as expected. For example, US Pat. Nos. 4,726,718, 5,199,832, 5,025,684, 5,238,074, 600,9963, incorporated herein by reference, describe various methods of mounting a plurality of PKA elements. Although many of these projects were commercially available, they were not able to combine the high wear and / or abrasion resistance with the corresponding impact strength of PCA that did not have thermal stability.

In US patent No. 497632, 5213248, 5337844, 5379853, 5496638, 5523121, 5624068, which are given in this case by reference, other types of diamond or diamond-like surface coatings are described. The same coatings are also described in British Patent Publication No. 2268768, PCT Publication No. 96/34131, EPG Publications No. 500253, 787820, 860515 for tool surfaces operating under high load. In these publications, diamond and / or diamond-like coatings are applied to surfaces to provide wear and / or erosion resistance.

Many of these publications describe methods for applying a diamond or diamond-like coating by chemical vapor deposition or vapor condensation. Chemical vapor deposition or vapor condensation methods are well known and described, for example, in US Pat. Nos. 5,439,492, 4,707,384, 4,645,977, 4,504,519, 4,486,286, which are hereby incorporated by reference.

Chemical vapor deposition and / or vapor condensation technologies can be used to deposit diamond or diamond-like coatings on a surface, for example, to produce sets of tightly packed, epitaxially oriented diamond crystals or other superhard crystals on the surface. Although these diamonds are very dense due to their tight packing, there is no strong bond between the individual diamond crystals, which makes them fragile and prone to cracking under high shear loads. As a result, despite the very high density of diamonds, they have low mechanical strength, very low impact strength and low wear resistance when working under high loads as cutting elements, bearings, friction elements and crimps.

In order to increase the strength and wear resistance of these diamond or diamond-like coatings, tungsten carbide substrates were used, followed by processing them under high pressure and at high temperatures, as described in US Patent Nos. 5,264,283, 5,496,638, 5,624,068, which are incorporated herein by reference. Although this type of processing can increase the wear resistance of the diamond layer, the abrupt transition from a high-density diamond coating to the substrate makes the diamond layer at the interface susceptible to cracking at very small residual strains, as discussed above when discussing composite structures with a barrier layer. This also leads to a decrease in operational strength and toughness.

If PKA elements made of cobalt or another binder-catalyzing metal of group VIII are used as a friction pair, then, as it turned out, when using the friction coefficient increases. As described in US patent No. 5560716, which is given in this case as a reference material, and in European patent No. 617207, it was found that the removal of the friction film from the surface of the PCA element that forms part of the bearing (by rubbing with hydrochloric acid), enriched in cobalt, the thickness of which gradually increases during operation, reduces the severity of this problem. It is obvious that during operation, cobalt migrates from the surface of the PCA to the bearing loading zone, thereby increasing friction between the PCA elements used as a friction pair. It is also obvious that the source of this cobalt may be the remaining by-product of the finishing of elements of friction pairs, since rubbing the surface with acid cannot effectively remove cobalt at great depths.

Since cobalt is removed only from the surface of the PCA, the temperatures at which the thermal destruction of these friction pairs occur do not significantly change. Therefore, the harmful effect of the binder-catalyzing material does not stop, and the presence of the catalyzing material continues to contribute to the thermal degradation of the diamond layer.

Summary of the invention

The present invention provides a superhard polycrystalline diamond or diamond-like element with significantly higher wear resistance without loss of toughness. Called in the present description, PKA elements, these elements are manufactured using a binder-catalyzing material at high temperature and high pressure. A PKA element consists of many partially interconnected diamonds or diamond-like elements forming the body of a continuous diamond matrix with a bulk density of diamonds of more than 85%. The intergranular zones located between the diamond crystals form a continuous intergranular matrix, which includes the catalyst material. A diamond matrix plate is formed and, using high temperatures and high pressure, this plate is connected to a substrate containing a catalytic material. The body of the diamond matrix has a working surface, while a part of the intergranular matrix of the body located in the immediate vicinity of the working surface is substantially free of catalytic material, while in the rest of the intercrystalline matrix, the catalytic material is present. Typically, less than 70% of the body of the diamond matrix plate is free of catalytic material.

The working surface, which is largely free of catalytic material, is not subject to thermal degradation occurring in other areas of the working surface, which provides increased wear resistance without loss of impact strength. A part of the outer plate of the body, a part of the peripheral surface of the body, or a part of all of these surfaces can be used as the treated working surface of the cutting elements.

In accordance with another embodiment of the present invention, cobalt or another element of the iron group is used as the catalytic material, and leaching from the intergranular zones in the region adjacent to the surface of the PCA element using acid etching technology is used as a depletion of the catalytic material. It is believed that in order to remove the catalyst material from the near-surface zone, an electric discharge or other electrical or galvanic process or evaporation can also be used.

Another method for manufacturing a PCA element is described, including a body made integrally with a metal-containing substrate, while the body includes diamond crystals and a catalytic material. In order to free the body volume from the catalytic material, its processing is carried out, while in some areas of the body the catalytic material remains, and the substrate is essentially not subjected to processing.

An element is described that includes a body, which includes many partially interconnected diamond crystals, a catalytic material, an intergranular matrix; the body has a work surface. The intergranular matrix of the body in the immediate vicinity of the working surface is substantially free of catalytic material, while in the rest of the intergranular matrix, the catalyst material is present.

A PCA element with a body including a catalytic material, an intergranular matrix, and a working surface is also described. The intergranular matrix of the body in the immediate vicinity of the working surface is substantially free of catalytic material, while in the rest of the intergranular matrix, the catalyst material is present.

In addition, a PCA element is described comprising a body with a working surface. The first body volume remote from the working surface includes catalytic material, and the second body volume in the area adjacent to the working surface is substantially free of catalytic material.

Also described is a PCA element containing diamond constituting a body made integrally with a metal-containing substrate. The body includes an intergranular matrix, and the bulk density of diamonds is 85%. The intergranular matrix of the body in the immediate vicinity of the working surface is substantially free of catalytic material, and the intergranular zones at the point of contact of the body with the substrate contain catalytic material and their average thickness is more than 0.15 mm.

In addition, a PCA element is described, including a body consisting of diamonds bonded together, which has a working surface made integrally with a metal-containing substrate. The bulk density of diamonds in the body is at least 85%. The first body volume, remote from the working surface, contains catalytic material, and the second body volume, located in the immediate vicinity of the working surface, is substantially free of catalytic material.

A PKA element is also described, including a body made integrally with a metal-containing substrate. The body includes many interconnected diamond crystals that have surfaces, and a catalytic material. The bulk density of diamonds in the body is at least 85%. At least 30% of the body diamonds are in contact with the catalytic material, and the surfaces of most other crystals located at least 0.1 mm deep into the working surface are substantially free of catalytic material.

In addition, a tablet-shaped cutting element is described. The cutting element has a body of superhard polycrystalline material, which includes many interconnected superhard crystals, made integrally with a metal-containing substrate, many intercrystalline zones located between superhard crystals, and a catalytic material. The body has a cutting surface, and the bulk density of diamonds in the body is at least 8 5%. Intergranular zones located in close proximity to at least part of the cutting surface are substantially free of catalytic material, and at least 30% of the remaining intergranular zones contain catalytic material.

PKA elements of the present invention can be used in conditions of friction, cutting, drawing and in other cases where technical superhard diamond surfaces are required. In particular, they can be used as cutting elements of a rotating drill bit with fixed or cone cutters, as crimps, a radiator, sliding bearings, surfaces of pipe fittings, indenters, toolholders, etc. PKA elements of the present invention can be used for abrasive processing of wooden products, black and non-ferrous materials, as well as for the processing of very hard or abrasive technical materials such as stone, asphalt, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1A shows a typical PKA element of the present invention. Figure 1B shows a typical PKA element of the present invention, used as a cutting element.

The figure 2 shows a side view of a blade chisel, which uses the PCA elements of the present invention.

Figure 3 shows a perspective view of a roller cone bit using the PKA elements of the present invention.

The figure 4 shows a perspective view of the insert with the PCA elements of the present invention, which is used for machining on machines.

The figure 5 shows a perspective view of a hemispherical PKA element for use in roller cone and vane drill bits.

The figure 6 shows a microphotograph of the surface of a PCA element of the prior art, which shows a binder-catalyzing material in the intergranular zones.

The figure 7 shows a micrograph of the surface of the PCA element of the present invention, which shows the first part with a catalytic material in the intergranular zones and the second part without a catalytic material in the intergranular zones.

The figure 8 shows the microstructure of a PCA element of the prior art, which shows interconnected diamond crystals with intercrystalline zones and the crystallographic orientation of individual crystals.

Figure 9 shows the microstructure of the PCA element of the present invention in accordance with Figure 7, which shows the depth of the zone free of catalytic material with respect to the surface of the PCA element.

Figure 10 shows a relative wear curve of several examples of PKA elements of the present invention.

Figure 11A is a front view of a variant of the PCA element of the present invention.

Figure 11B is a sectional view of another embodiment of a PCA element of the present invention.

11C is a cross-sectional view of yet another embodiment of a PCA element of the present invention.

12A is a perspective view of a coated surface obtained by chemical vapor deposition or vapor condensation for another embodiment of the PCA element of the present invention.

Figure 12B is a perspective view of an enlarged crystal structure of a variant of the PCA element of the present invention in accordance with Figure 12A.

The figure 13 shows a cross-section of a die for wire drawing with the PCA element of the present invention.

Figure 14 is a perspective view of a radiator with a PCA element of the present invention.

15 is a perspective view of a bearing with a PCA element of the present invention.

Figures 16A and 16B show a front view of the mating parts of the pipe fitting with the PCA element of the present invention.

17A is a side view of an indenter with a PCA element of the present invention.

Figure 17B shows a section of a punch with a PKA element of the present invention.

Figure 18 shows a perspective view of a measuring device with a PCA element of the present invention.

The figure 19 shows the dependence of the resistance to abrasion on the toughness of the cutting elements of the prior art in comparison with the dependence for the cutting element of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION AND PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Figure 1A shows an element 2 of polycrystalline diamond or diamond-like (PKA) material of the present invention. A PCA element 2 includes a plurality of partially interconnected superhard, diamond or diamond-like crystals 60 (figures 7 and 9), a catalytic material 64 and an intercrystalline matrix 68 consisting of intercrystalline zones 62 located between the crystals 60. Element 2 also includes one working surface or two working surfaces 4, and diamond crystals 60 and intercrystalline zones 62 form the volume of the body 8 of the PCA element 2. It is desirable that the element 2 was made integral with the metal-containing substrate 6, which is usually made of carbide in lframa, with cobalt as a binder. To ensure effective use in abrasive wear, the bulk density of diamonds in body 8 should be more than 85%, but it is better that this value is more than 90%.

The working surface 4 is any part of the PCA-body 8, which during operation can come into contact with the processed object. When considering the working surface 4 in this description, it is understood that it is applied to any part of the body 8, which may be affected and / or which can be used as a working surface. In addition, any part of any work surface 4 is itself a work surface.

In the manufacture at high temperatures and high pressures, the intercrystalline zones 62 located between the crystals 60 are filled with a catalyst material 64, followed by the formation of bonds between the crystals 60. In the next manufacturing step, some intercrystalline zones 62 are selectively depleted in the catalyst material 64. As a result, it turns out that the first body volume 8 of the PCA element 1, remote from the working surface 4, includes a catalytic material 64, and the second body volume 8, located in close proximity and from surface 4, substantially free of catalytic material 64. Intercrystalline zones 62, which are substantially free of catalytic material 64, are indicated by 66.

Thus, the intergranular matrix 68 of the body 8, located in close proximity to at least part of the working surface 4, is substantially free of catalytic material 64, and the rest of the intergranular matrix 68 contains the catalytic material 64. As noted earlier, the PCA element 2 with By means of high temperatures and high pressures, it can be connected to a substrate 6 made of a less hard material, usually sintered tungsten carbide, but the use of substrate 6 is not necessary.

Since the body in the immediate vicinity of the working surface 4 is substantially free of catalytic material 64, the negative effect of the binder-catalyzing material 64 is significantly reduced, which eliminates the thermal degradation of the working surface 4 caused by the presence of the catalytic material 64. As a result, a new PKA-element 2 with improved thermal properties approaching the thermal properties of the so-called thermally stable PKA-elements while and strength, manufacturing and the ability to form communication technology inherent in conventional polycrystalline diamond compact elements (PAA-elements). This provides higher wear resistance during cutting, higher heat transfer when using PKA as radiators, higher bearing capacity when using PKA as bearings, reduces surface destruction when using PKA in pipe fittings. There are advantages when using PKA in other cases, including the use of crimps, indenters, toolholders and friction elements. These advantages are achieved without loss of toughness of the element. Below, the application of the new PKA elements 2 is considered in more detail.

We now turn to the micrograph of the PCA element of the prior art in figure 6, as well as the microstructure of the PCA element of the prior art in figure 8, from which the random crystallographic orientation of diamond or diamond-like crystals 60 is visible, which is seen from parallel lines representing the cleavage planes of each crystal 60. As can be seen, neighboring crystals 60 are connected to each other by intercrystalline zones 62 located between them. Since the cleavage planes of neighboring crystals 60 are oriented in azlichnyh directions, there is no straight path on which a fault may occur diamond. This structure allows PKA materials to withstand extreme loads with high impact loads.

In the process of bonding the crystals 60 in the press at high temperature and pressure, the intergranular zones 62 located between the crystals 60 are filled with a binder-catalytic material 64. It is the catalytic material 64 that binds adjacent diamond crystals 60 at relatively low pressures and temperatures in the press.

The PCA element of the prior art has at least one continuous matrix of crystals 60 connected to each other by intercrystalline zones 62 containing a binder-catalytic material 64, usually cobalt or another element of group VIII. Crystals 60 constitute the first continuous matrix of diamonds, and intercrystalline zones 62 form a second continuous matrix of intercrystalline zones 62, known as intercrystalline matrix 68, containing a binder-catalyzing material. In addition, it is necessary that relatively small areas to ensure the growth of diamonds include a binder-catalytic material. These islands are not part of the continuous intergranular matrix 68 of the binder-catalyst material 64.

In figures 7 and 9 shows a cross section of the PCA element 2 of the present invention. A PCA element 2 can be formed in the same way as a PCA element of the prior art. According to a preferred embodiment of the invention, in the manufacturing process immediately after the preliminary cleaning operation or at any other time after this operation, the working surface 4, 70, 72 of the PCA element 2 is treated so that part of the binder-catalyzing material is removed from the body. As a result, the intergranular zones 62 located between the diamond crystals 60 in the immediate vicinity of the working surface become substantially free of the catalytic material 64, indicated at 66. The portion of the working surface 4, 70, 72, which is free of the catalytic material 64, is not It is subject to thermal degradation that occurs in other areas of the PKA, which provides improved thermal characteristics.

The average bulk density of diamonds in body 8 of the PCA element 2 of the present invention is in the range of 85 to 99%. A high bulk density of diamonds is achieved using 60 diamond crystals with average particle sizes of 30 to 60 microns. Typically, a diamond mixture may include from 20 to 60% of diamond crystals 60 with a size of 5-15 microns, from 20 to 40% of diamond crystals 60 with a size of 25-40 microns, and from 20 to 40% of diamond crystals 60 with a size of 50-80 microns in diameter, although other particle size ranges may be used. A mixture of large and small diamond crystals 60 allows diamond crystals 60 to give a relatively large proportion of their surface, often reaching 95%, to the bonds between diamonds, which contributes to the relatively high relative abrasion resistance.

There are many ways to remove the catalyst material 64 from the intergranular zones 62 or to reduce its content in these zones. In accordance with one of the methods, the catalyst material 64 is cobalt or another material of the iron group, and the method of removing the catalyst material 64 is to leach it from intercrystalline zones 62 in the area adjacent to the working surface 4, 70, 72 of the PCA element 2, using technology acid etching to a depth greater than about 0.2 mm. To remove the catalytic material 64 from the near-surface zone, an electrical discharge or other electrical or galvanic technology or evaporation can be used.

According to another method for reducing the content of the catalyst material 64 in the intergranular zones 62, the reduction in the content of the catalyst material 64 is achieved by the formation of a chemical compound, for example, fusion with another material, so that it is no longer a catalyst material. According to this method, the material may remain in the intergranular zones between the diamond crystals 60, but this material is no longer a catalyst material 64, which corresponds to its effective removal.

According to yet another method for reducing the content of the catalyst material 64 in the intergranular zones 62, the catalyst material 64 is removed by converting it into a material that is no longer a catalyst material. This can be achieved by changing the crystal structure, phase transformation, machining, heat treatment, or using other processing methods. Such a method can be applied to non-metallic or chemically inactive catalyst materials. In addition, the material may remain in the intergranular zones 62 between the diamond crystals, but this material is no longer a catalyst material 64, which corresponds to its effective removal.

As soon as the catalytic material 64 in the immediate vicinity of the working surface 4, 70, 72 loses its effectiveness, the PCA element 2 of the present invention loses its sensitivity to thermal degradation, which is known to occur in the PCA elements of the prior art. As described above, there are two modes of thermal degradation, which are known to be caused by the catalytic material 64. The first mode of thermal degradation begins at temperatures of approximately 400 ° C and occurs as a result of the difference in thermal expansion of the binder-catalytic material 64 in the intergranular zones 62 and crystals 60 After a sufficient expansion of the bond between the diamonds can be broken and cracking and chips can occur.

The second regime of thermal degradation begins at temperatures of approximately 750 ° C. This mode is caused by the catalytic ability of the binder-catalytic material 64, which reacts with the crystal 60, and leads to graphitization of the crystal 60 as the temperature approaches 750 ° C. With the graphitization of crystals 60, they sharply increase in volume, which leads to cracking and loss of bonds with the body 4. Even the presence of a catalytic material 64 several microns thick on the surfaces of diamond crystals 60 can cause this mode of thermal destruction.

Those skilled in the art will appreciate that, optimally, the catalyst material 64 should be removed from the intergranular zone 62 located between the diamond crystals 60, as well as from the surfaces of the diamond crystals 60. If the catalyst material 60 is removed both from the surfaces of the diamond crystals 60 and from the intergranular zones, then the thermal destruction of diamond crystals 60 in this area begins only when 1200 ° C is reached.

However, this double destruction mode leads to some unexpected advantages. For example, in many cases it is necessary to calculate the wear rate of the work surface. In accordance with the present invention, this can be done by changing the processing technology so that in areas where maximum wear resistance is required, the content of the catalyst material decreases both in the intergranular zones 62 and on the surfaces of diamond crystals 60. And in those areas where it is required less high wear resistance, for example in the case of a self-sharpening tool, these areas are processed so that the content of the catalyst material 64 decreases primarily in the intergranular x zones 62, but some or all of the diamond crystals 60 remain in contact with the catalyst material.

It is also obvious that it is more difficult to remove the catalytic material 64 from the surfaces of the diamond crystals 60 than from the intergranular zones 62. For this reason, depending on the method of reducing the content of the catalytic material in order to reduce thermal degradation, the depth by which this region is depleted of the catalytic material 64, counting from the working surface 4, may vary depending on the method of reducing the content of catalytic material 64.

In some cases, raising the heat threshold to about 400 ° C, but less than 750 ° C is equivalent in its effect, and therefore less intensive technologies for reducing the content of catalytic material 64 can be applied. As a result, it should be understood that to ensure the required level of depletion of this region with catalytic material 64, you can combine a variety of ways to reduce the content of catalytic material 64.

When used in this description, the expression "substantially free from" with respect to the catalytic material 64 in the intergranular zones 62, the intergranular matrix 68 or the volume of the body 8 it should be understood that many, if not all, of the surfaces of adjacent diamond crystals 60 can be coated with a catalyst material 64. Moreover, when using the expression “substantially free of” with respect to the catalyst material 64 on the surfaces of the diamond crystals 60, the catalyst material 64 may still remain in adjacent zones 62 intercrystalline.

When removing or reducing the content of the catalyst material 64, the two main mechanisms of thermal degradation no longer work. However, it was found that the catalytic material 64 should be removed to a sufficient depth with the removal of heat generated as a result of heat generation, from the bound crystals 60 from the zones of presence of the catalytic material 64 to a level that provides a temperature below the temperature of destruction of the crystals 60.

In one series of laboratory tests, the PKA element 2, made in the form of a cutting element 10, was informed of heat. Since these tests were planned as standard wear tests for these cutting elements, it was possible to compare the cutting elements 10 with different depths of removal of the catalyst material 64. In these tests, attention was paid to the removal of the catalyst material 64 both from the intergranular zones 62 and from the diamond surfaces crystals 60. The test was planned in such a way that heat was supplied periodically to the cutting edge of the cutting PKA element 10 for a certain time.

After completion of the tests, the wear indicator was calculated. The higher the wear rate, the better the wear resistance. According to the nature of the tests, it was assumed that an increase in the wear indicator means an increase in the resistance to thermal destruction of the working surface 70, 72 of the cutting element 10.

As can be seen from curve A (figure 10), if the depth of removal of the catalytic material 64 reaches 0.1 mm, then there is a sharp increase in the wear rate of the cutting elements 10. Therefore, with the usual supply of heat to the cutting elements 10, a depth of 0.1 mm is a critical depth of removal catalytic material from the working surface 4, 70, 72, if the catalytic material 64 is removed both from the intergranular zones 62, and from the surfaces of diamond crystals 60.

Curve B (figure 10) shows the dependence of wear on the depth of removal in other tests of the cutting elements 10 made using the more economical technology for removing the catalytic material 64. The technology for removing the catalytic material 64 used in the manufacture of these cutting elements was not so effective in removing the catalytic material 64 from the surfaces of diamond crystals 60, as a technology that provides the results shown on curve A. Therefore, a result similar to the result appeared on the curve A may be achieved only when the catalyzing material 64 is removed from the intergranular region 62 to a depth of about 0.2 mm. It was found that the toughness of these cutting elements 10 did not differ significantly from the toughness of the raw elements.

We turn now to figure 19, which clearly demonstrates the increase in wear resistance while maintaining toughness; the typical dependence of toughness on abrasion resistance obtained for cutting elements of the prior art and shown as a dependence of W. is well known. Point P in the graph shows the properties of the cutting element of the present invention. As you can see, the point P lies in the upper right corner of the graph, which indicates a significant and consistent increase in the wear resistance of the cutting elements while maintaining the toughness.

Obviously, the dependence C (FIG. 10) can be applied to the PKA elements 2, according to which thermal degradation can be determined depending on the wear rate. For example, it may be required that the edges of the curvature of the cutting elements 10, remote from the center of contact, wear out faster than the center point. This will ensure the preservation of the curvature of the cutting element.

An increase in resistance to thermal degradation increases wear resistance, since diamond is an exceptionally good heat conductor. If the friction of the working surface 4, 70, 72 leads to a sudden, excessive heat generation, then bound diamond crystals conduct heat in all directions. This leads to an excessively large temperature gradient, which can be 1000 ° C per 1 mm or higher. Moreover, the temperature of the working surface 4, 70, 72 can reach 950 ° C, which will not cause significant thermal degradation if the intergranular zones 62 and the surfaces of diamond crystals 60 in the immediate vicinity of the working surface are substantially free of catalytic material 64 to a depth of approximately 0.2 mm from the heat source.

Obviously, the temperature gradient varies depending on the size of the crystal 60 and the bonding strength between the crystals. This can be explained by the bulk density of diamonds in the body 8. When using conventional manufacturing methods with increasing bulk density of diamonds, the temperature gradient on the material also increases. This suggests that the wear rate of the same material, the characteristics of which correspond to curve B in figure 10, with increasing bulk density of diamonds will tend to curve A.

However, during operational tests of cutting elements 10 for rock cutting heads, the removal of all the catalytic material 64 from intercrystalline zones 62 by a distance D equal to approximately 0.2-0.3 mm from the working surface 4, 70, 72 led to a sharp increase in wear resistance, while in addition to a 40% increase in wear resistance, a 40% increase in penetration rate was also observed. The increase in wear resistance shows that the abrasion of diamond crystals 60 as a result of thermal degradation caused by the catalyst material 64 was significantly reduced. Obviously, the increase in penetration rate occurs as a result of the fact that the cutter remains sharp longer due to increased wear resistance.

It is obvious, however, that as the bulk density of diamonds in body 8 increases from 85-90% to 95-99%, the distance D necessary to obtain the corresponding wear indicator will increase. Therefore, it is also obvious that the distance D less than 0.1 mm will provide approximately the same wear rate of the cutting element with a diamond density in the body of 99%, as well as the distance D equal to approximately 0.2-0.3 mm in the body with a bulk density of diamonds 85 -90%.

When removing the catalyst material 64 from the intergranular zones 62, it is important that the catalyst material is not removed from the underlying substrate 6, 32. Therefore, it is very important that the catalyst material 64 remains in the intergranular zones, at least part of the diamond layer, 64. It was found that when removing of the catalytic material 64 from a flat surface having a flat interface with the substrate 6, 32, it is necessary to leave a layer of a minimum thickness of 0.15 mm containing the catalytic material 64, which will prevent the removal of the catalytic mat Series from the underlying substrate 6, 32.

It is difficult to determine this value for PAR, since some depletion of the substrate by the catalyst material is allowed, and the geometry of the PAR can be complicated. However, in accordance with one method of determining this value in the intergranular zones 62 of that part of the body 8 that is in contact with the substrate 6, 32, the catalytic material 64 must remain in an area whose average thickness is more than 0.15 mm.

Another way to determine this value is to express the minimum amount of catalyst material 64 remaining in the intergranular zones 62 as a volume fraction. It is known that with a very thin, flat diamond layer, it is necessary that, with a body thickness of 0.5 mm, the thickness of the layer containing the catalytic material 64 is 0.15 mm. Therefore, it can be assumed that for the PAR elements of the present invention, the sizes of which, in particular, correspond to the sizes of typical PAR, the minimum body volume of 8, in the intergranular zones 62 of which should be the catalyst material 64, is 30%.

PKA elements can be of another design, which allows you to get the benefits of reducing the content or removal of the catalytic material 64, as described above. As shown in FIGS. 11A, 11B, and 11C, another embodiment of the present invention is a composite PCA element 102. The PCA element 102 has a body 108 made of a binder-catalyzing material from group VIII and a second PCA element 110 buried therein. The recessed PKA element 110 may be flush with the working surface 104 of the PKA element 120, as shown in FIG. 11A, or it may be completely recessed into the PKA element 120, as shown in FIG. 11B. This recessed PKA element 110 is manufactured using a technology in which Mg, Ca, Sr and Ba carbonate powder is used as a binder-catalyzing material, which is molded into a composite PKA element, as described in US Patent Application Serial No. 09/390074, which given in this case by reference.

In this embodiment, since the PCA element 110 which is buried, compressed into a tablet is molded under high pressure, the density of diamond may be higher than the density of the PCA element 120. Since the composition of the PCA element 110 to be buried includes a catalytic material with a higher activation temperature, it may be more correct to reduce the content of the catalytic material only on the working surface of the PCA element 120. In addition, the buried PKA element 110 can be placed inside the PKA element 120 to combine the advantages of more sokoy toughness deepens PCD element 110 with increased wear resistance PCD element 120.

As shown in figures 9, 11A, 11B and 11C, the element 102 includes many partially interconnected diamond crystals 60, a catalytic material 64 and a body 108 with a working surface 104. The density of diamonds in the immediate vicinity of the working surface 104 of the volume 112 of the body is significantly higher than the density diamonds elsewhere in volume 114 of body 108, and volume 112 is substantially free of catalytic material 64.

Several buried PKA elements 110 can be located in the composite element 100, as shown in figure 11C, so that provides the highest impact strength and increased wear resistance.

It may be necessary to reduce the content of catalytic material in the buried PKA element 110, as well as the catalytic material in the PKA element 120. This combination provides the highest possible toughness in combination with the highest possible wear resistance of mass-produced diamond elements.

Figures 12A and 12B show another embodiment of the PCA element 202 of the present invention. In accordance with this embodiment, the PCA element 202 is first manufactured in accordance with the prior art. After surface preparation, chemical vapor deposition or vapor condensation technology is applied to deposit on a future work surface 204 of part 210 of the PCA element 202 of a densely packed set of epitaxially oriented diamond crystals 260. Then, the assembly is subjected to high pressure and temperature, whereby the deposited diamond crystals 260 form intergranular bonds with each other and with diamond crystals of the initial PKA. The bonding of diamonds to each other is possible due to the presence of a catalytic material 64, introduced from the surface of the original PKA element 202.

After cleaning, part of the working surface 204 is processed in order to reduce the content of the catalytic material 64 from the layer obtained by chemical vapor deposition or vapor condensation. The finished product is a PCA element, one part of which is a work surface 204, in the volume 214 of which the density of diamonds is much higher than the density of diamonds on other surfaces 280 of the PCA element 202. Parts of other surfaces 280 of the PCA element 202 can also be depleted in binder -catalytic material.

In general, the elements 102, 202 shown in FIGS. 11A, 11B, 11C, 12A, and 12B may be characterized as a PCA element 102, 202 with a body 108, 208 with a working surface 104, 204. The density of diamonds in the immediate vicinity of the working surface 104 , 204 are significantly higher than the density of diamonds in other parts of the body 108, 208, which are substantially free of catalytic material 64.

As shown in figures 1B, 4 and 5, the PCA element 2 of the present invention can be used as cutting elements 10, 50, 52. The working surface of the cutting PCA element 10, 50, 52 can be in the form of an upper working surface 70 and / or peripheral work surface 72. The PCA cutting element 10 of FIG. 1B can typically be used in the heads of the blade 12 or to protect the calibrating surface of the drill bit in other types of drilling tools. The cutting PCA element 50 shown in FIG. 5 may be in the form of a hemisphere 39. This type of cutting PCA element has an elongated base 51, which is mounted in the roller cone bit 38 or in the body of both types of rotating bits 12, 38, which will be described below.

Cutting PKA-element 52, depicted in figure 4, is intended for use in machining on machines. Although figure 4 shows a cutting element 52 of rectangular cross section, specialists understand that this element can be triangular, square section or any other shape suitable for machining abrasive materials that are difficult to machine with a conventional tool.

The cutting PKA-element 10 can be made in the form of a blade element 12 pressed into a tablet cutting element 10 (figure 2). The body of the head 14 of the bit has many blades 16 extending from the center of the longitudinal axis of rotation of the 18 bits. On the front surface 20 of each blade is a plurality of cutting PKA elements 10 of the present invention.

Typically, the cutting PKA element 10 has a body in the form of a round tablet with a thin front outer plate 30 made of diamond or diamond-like material (PKA), which is connected in the press under high pressure and at high temperature with a substrate 32 made of a less hard material of the type sintered tungsten carbide. The cutting element 10 is pressed into a tablet and then usually connected to a cylindrical holder 34, which is also molded from sintered tungsten carbide, or can be directly attached to the blade. The cutting PCA element 10 has working surfaces 70 and 72.

The cylindrical holder 34 is mounted in a socket or a recess of a corresponding shape made in the blade 16. In the socket, the holder 34 is usually soldered or mounted on a hot seat. During operation, the blade bit 12 rotates. The mass of the bit is set in motion and causes the cutting elements to cut into the rock, which provides cutting and / or drilling.

The cutting PCA elements 10 can also be mounted on the calibrating surface 36 of the drill bit 12 to expand the borehole, as well as to protect the bit 12 from excessive wear in the area of the calibrating surface 36 of the drill bit.

In accordance with the second embodiment, the cutting element 50 (figure 5) of the present invention is mounted on the roller bit 38 (figure 3). A cone bit 38 usually has one to several cones 40, 41, 42, made in the form of a truncated cone, mounted on the pin of the paw 44 of the bit body 46. The cutting elements 50 can be installed in the form of one or more cutting inserts arranged in rows of cones 40 , 41, 42, or in another case, the cutting PKA-elements 50 may be located on the paw 44 of the bit 38. The cutting PKA-element 50 has a body in the form of an outer plate 35 of diamond or diamond-like material connected to a less solid substrate 37. In accordance with this option of the present invention, the outer plate 35 is made in the form of a hemispherical surface 39 and has working surfaces 70 and 72. Therefore, numerous transition layers are often installed between the outer plate 35 and the substrate 37, which helps to more evenly distribute the stresses that occur during manufacture, which is well known to specialists.

During operation, roller cone 38 rotates. The mass of the bit is set in motion and causes the cutting inserts 50 located on the cones 40, 41, 42 to cut into the rock, and as the bit 36 rotates, the cones 40, 41, 42 rotate, which ensures drilling.

In accordance with another embodiment of the present invention, the cutting PCA element 52 is made in the form of a triangular, rectangular or other shape of the product, which is used as a cutting insert for machining on a machine. According to this embodiment of the present invention, the cutting element 52 has a body in the form of an outer plate 54 of diamond or diamond-like material connected to a weaker substrate 56 with working surfaces 70 and 72. Usually, after this, the cutting element 52 cuts into many smaller pieces interlocked with an insert 58, which is mounted in the tool holder of the metal cutting machine. The cutting element 52 can be mounted on the insert by soldering, gluing, welding or collar. You can also install the cutting element 52 of the insert by pressing at high temperature and high pressure.

As shown in figures 13-18, the PCA elements 2, 102, 202 of the present invention can also be used in other cases, for example in crimps, shown, for example, in figure 13 in the form of dies for drawing wire 300, which uses PKA- element 302 of the present invention. Excellent thermal conductivity properties of the PCA element 2, 102, 202 in combination with its electrical insulating properties for use as a radiator 310 with the PCA element 312 of the present invention may also be required.

Figure 15 shows the use of the PCA element 322 in a plain bearing 320, and figures 16A and 16B show the mating parts of the pipe fittings 340, 344 with the surfaces 342 of the PCA element 342 of the present invention. In addition, FIG. 17A shows indenters 360 for use in engraving, as hardness testers, for notching surfaces and the like, in which the PCA elements 362 of the present invention can be used. As shown in FIG. 17B, in the punches 370, either one or both of the counter elements 372, 374 can be made from the PCA material of the present invention. In addition, toolholders 382 and other types of friction elements for measuring devices 380 shown in FIG. 18 can be made from the PCA elements of the present invention. It should be understood that in almost all cases of using polycrystalline diamond, the use of PKA elements depleted in the catalyst material of the present invention is useful.

In the light of the description of the present invention, it should be understood that in some cases deviations from the options shown or proposed here are possible, which, however, do not change essentially the scope and essence of the present invention.

Claims (11)

1. A tablet-shaped cutting element comprising a body made of a superhard polycrystalline material with a plurality of diamond crystals bonded to each other, made integrally with a metal-containing substrate, with a plurality of intergranular zones located between the diamond crystals, and with a catalyst material, wherein the bulk density diamonds in the body is at least 90% and the body has a cutting surface, while the second intergranular zone located in close proximity to at least an hour and the cutting surface is substantially free of catalytic material, while the first intergranular zone of that part of the body that is in contact with the substrate contains the catalytic material, and the second intergranular zone extends deep into the cutting surface, and the average thickness of the first intergranular zone is more than 0 , 15 mm. 2. Compressed into a tablet cutting element according to claim 1, characterized in that the cutting element is installed on the cutting edge of the blade bit. 3. Compressed into a tablet cutting element according to claim 1, characterized in that the cutting element is installed on the roller cone body. 4. Compressed into a tablet cutting element according to claim 1, which is part of the cutting element with a cutting surface, intended for use as a cutting insert for machining on machines. 5. The cutting element compressed into a tablet according to claim 1, characterized in that the substrate is made of tungsten carbide with a binder from the iron group. 6. Compressed into a tablet cutting element according to claim 1, characterized in that the second intergranular zone extends into the depth of the cutting surface by at least an amount equal to the average diameter of the diamond crystal. 7. Compressed into a tablet cutting element according to claim 1, characterized in that the second intergranular zone extends into the depth of the cutting surface by at least 0.1 mm 8. Compressed into a tablet cutting element according to claim 1, characterized in that the average size of the diamond crystal is in the range from about 30 microns to 60 microns. 9. The tablet-shaped cutting element according to claim 1, characterized in that most of the catalytic material of the first intergranular zone of the body adheres to the surfaces of diamond crystals. 10. A tablet-shaped cutting element according to claim 1, characterized in that the amount of catalyst material in the second intergranular zone of the body continuously decreases as the distance from the first volume increases. 11. Compressed into a tablet cutting element according to claim 1, characterized in that the first intergranular zone remote from the working surface is more than 30% of the body.

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