KR20120132679A - A superhard insert and an earth boring tool comprising same - Google Patents

Abstract

The ultrahard insert for a rotary ground perforator comprises a cutter end having a peripheral cutter edge, at least a portion of which is formed by a plurality of edges of a plurality of alternating hard and ultrahard regions. The edges of the hard zone are spaced apart from each other and separated by the edge of the hard zone. The hardness of each hard zone is 50% or less of the hardness of each superhard zone.

Description

Super hard insert and ground drilling machine comprising same {A SUPERHARD INSERT AND AN EARTH BORING TOOL COMPRISING SAME}

The present invention relates to an ultrahard insert for a rotary ground perforator.

Rotary ground drills are used to drill ground in industries such as oil and gas exploration, well development and construction. The rotary drill bit for rock drilling may comprise a plurality of ultrahard inserts mounted to the drill bit body. In use, the head is rotated at high speed with great force to remove rock material by shear cutting action by rotating the ultrahard insert about the wall and end of the hole. Inserts suitable for this use may be referred to as “shear cutter” inserts and may include a layer of polycrystalline superhard material bonded onto a cemented carbide substrate. One example of a polycrystalline superhard material is polycrystalline diamond (PCD).

PCD is a superhard material that contains a gap between diamond particles and agglomerates of internally grown diamond particles. PCD can be made by exposing agglomerated masses of diamond particles to very high pressure and very high temperatures. PCD is used in a wide range of tools for cutting, machining, drilling or dismantling hard or abrasive materials such as rock, metal, ceramics, composites and wood-containing materials. For example, PCD inserts are widely used in drill bits for drilling ground in the oil and gas mining industry. In many of these applications, the temperature of the PCD material is raised when it is combined with the rock layer, workpiece or body.

EP 0 278 703 discloses an abrasive body having a sintered carbide core and abrasive cutting corners, wherein the abrasive cutting corners can be the same material or different materials. The abrasive body may comprise a layer of bonded ultrahard abrasive particles bonded to the substrate, and the ultrahard abrasive particles may be diamond or cubic boron nitride.

PCT Patent Application Publication WO 2002/022311 discloses a tool insert comprising a sintered tungsten carbide substrate having a plurality of pre-sintered recesses formed therein. One embodiment of a tool insert consists of a section of a substrate to which four abrasive bodies are bonded to each of the four corners of the section.

U. S. Patent No. 5,607, 024 discloses an ultra hard insert with a cutter end mounted on a support member. The cutter end is in the form of a disk or tablet shape having polycrystalline diamond particles bonded in a binder consisting mainly of cobalt. This tablet or disc is then fixedly attached to the cylindrical support member by conventional high temperature high pressure sintering treatment.

US Pat. No. 7,533,740 discloses a cutting element having a substrate having an end face and a periphery, the end face extending to the periphery, and the "TSP" material layer being formed over a portion of the end face and extending to the periphery. . In one embodiment, the TSP is mechanically locked by the cutting element.

As ultrahard inserts for rotary ground boring machines, there is a need for ultrahard inserts having low cost or good properties, in particular for drilling ground or mining or decomposing rock layers.

As used herein, "superhard" means a Vickers hardness of at least 25 GPa.

In a first aspect, an ultrahard insert for a rotary ground perforator comprising a cutter end having a peripheral cutter edge, wherein at least a portion of the peripheral cutter edge is defined by a plurality of edges of a plurality of alternating hard and ultrahard regions. And the edges of the superhard regions are spaced apart from each other and separated by the edges of the hard regions, with the hard insert being provided with a hardness of 50% or less of the hardness of each hard zone.

In use to enhance the cutting effect of the superhard region, the edge of the hard region may wear out faster than the edge of the superhard region.

In some embodiments, at least some of the peripheral cutter edges are angular, rounded, chamfered or inclined.

As used herein, the rake surface is the surface of the cutting insert through which the material removed by the cutting action of the ultrahard insert flows over it, which material is commonly referred to as a "chip." The rake angle is the angle of inclination of the rake surface with respect to the surface of the workpiece or other body being cut, drilled or disassembled, the positive rake angle may cause the chip to move away from the workpiece and the negative rake angle to direct the chip towards the workpiece. do.

In some embodiments, the cutter end has a plurality of rake surfaces. The plurality of rake surfaces can be inclined at different angles with respect to each other, can be disposed radially between the peripheral cutter edge and the area farther from the peripheral cutter edge, starting from the peripheral cutter edge, the first face, the second face, etc. Can be specified.

In some embodiments, the cutter ends comprise two, three, four, five or even ten or more edges of the hard zone.

In some embodiments, the hard insert has a generally cylindrical or disc shaped form. In some embodiments, the hard insert has substantially 2-fold, 3-fold, 4-fold or even 5-fold rotational symmetry around the central axis when viewed in plan view of the cutter end.

The hard insert may in some embodiments be reusably mounted on a tool to help reduce the effective cost of the hard insert by extending its working life.

In one embodiment, the cutter end includes a hard center region distant from the peripheral cutter edge and is centered between the plurality of superhard regions. In one embodiment, the central hard zone has ridges or bosses. The ridges or bosses may be integrally formed with the support or fixed to the support by mechanical, brazing or gluing means.

In some embodiments, the ridges or bosses advantageously function as chip breakers in use, and chips formed from materials that are punctured or degraded are deflected away from the cutter, thus reducing wear on the cutting surface.

In one embodiment, the cutter end includes at least one cutter face suspended downward from the ridge or boss toward the peripheral cutter edge.

The negative rake angle can be achieved without the need to modify the angle at which the hard insert is fixed to the tool carrier.

In one embodiment, the ultrahard region lies on the rake face having a positive rake angle. In one embodiment, the central region includes a ridge or boss portion, with the portion of the rake face suspended from the ridge or boss portion and the other portion of the rake face adjacent the peripheral cutter edge upwards to form a positive rake angle. Extending, resulting in a scoop-shaped feature on the cutter end.

In one embodiment, each superhard region has a marker to identify it.

Two or more superhard regions with different hardness or other properties can be easily identified. The user can use the marker to select the superhard area that is most suitable for the desired use or workpiece material (eg, in the form of a rock layer). In one embodiment, the marker may be inscribed in the hard area adjacent to each ultra hard area.

In some embodiments, the ultrahard insert includes a plurality of spoke structures projecting radially outwardly, each spoke having a superhard structure.

In some embodiments, each of the at least one superhard region has sides that generally converge or generally diverge when viewed in plan view of the cutter end. Such an embodiment may be configured to have a nearly constant edge length as the area wears in use or otherwise an ultrahard edge length as needed.

The length of the edge can be kept almost constant throughout the working life of the ultrahard insert, thus extending the performance of the cutter as it gradually wears out during use.

In some embodiments, the Vickers hardness of each superhard region is at least about 40 GPa, at least about 50 GPa, or at least about 60 GPa. In some embodiments, at least one of the ultrahard regions comprises a material having an average Young's modulus of at least 900 GPa, at least about 1,050 GPa, or at least about 1,100 GPa.

In some embodiments, each hard region has a hardness of at least 20% or at least 30% of each superhard region. In one embodiment, each hard region comprises a sintered tungsten carbide material.

In one embodiment, the ultrahard insert includes a plurality of ultrahard structures comprising an ultrahard material, the ultrahard structure being bonded, clamped or otherwise bonded to the support. In some embodiments, the support comprises a material having an average Young's modulus of at least about 60%, at least about 70%, or at least about 80% of the average Young's modulus of each of the ultrahard regions.

In general, the smaller the difference in average Young's modulus between the support and the superhard structure, the more robust the cutter insert can be and the less risk that the superhard structure will separate or break from the support.

In one embodiment, the support comprises sintered tungsten carbide.

In one embodiment, the support comprises an ultrahard material such as diamond or cubic boron nitride (cBN) in particle or particulate form.

The presence of an ultrahard material in the support can have the effect of increasing the rigidity of the ultrahard insert and can reduce the risk of destruction of the ultrahard structure.

In some embodiments, at least one of the ultrahard structures is secured to the support by pins, rivets, bolts or the like, or clamped to the support by clamping means. In some embodiments, the support includes through holes configured to receive securing pins, rivets, bolts, and the like. In some embodiments, retaining pins, rivets, bolts, and the like are threaded.

Some embodiments may be particularly suitable for being secured to the tool body by pin or screw means because they are not superhard and have a central area in which through holes can be formed to receive pins, rivets or screws.

As used herein, "polycrystalline diamond" or PCD means a material comprising a mass of substantially internally-grown diamond particles that forms a skeletal structure with a gap between the diamond particles, the material Contains more than 80% by volume diamond.

In one embodiment, each superhard region comprises a PCD material, preferably a thermally stable PCD. In some embodiments, the PCD material has a diamond content of at least about 88 volume percent or at least about 90 volume percent. In some embodiments, the PCD material has a diamond content of about 99 volume percent or less.

In some embodiments, at least one of the plurality of ultrahard regions comprises a PCD material made by a method comprising exposing the PCD or precursor thereof to a pressure greater than about 6 GPa, greater than about 7.0 GPa or even greater than about 8.0 GPa. Include.

Some embodiments in which the ultrahard structure comprises a PCD may have high pressures that may be sufficient to result in improved diamond proximity and improved interparticle bonding, more homogeneous spatial distribution of diamond particles, lower porosity and lower total solvent / catalyst content. It may comprise a sintered PCD, the PCD may have a higher hardness, wear resistance and modulus or Young's modulus.

In some embodiments, at least one of the plurality of ultrahard regions comprises PCD material comprising diamond particles having an average diamond particle proximity of at least about 60.5 percent or at least about 61.5 percent. In general, the higher the diamond particle proximity, the lower the likelihood of breaking the hard insert.

In some embodiments, at least one of the plurality of ultrahard regions comprises a PCD material having a mean free path between gratings of at least about 0.05 microns, at least about 0.1 microns, at least about 0.2 microns or at least about 0.5 microns. . In some embodiments, at least one of the plurality of ultrahard regions comprises a PCD material having an interstitial mean free path of 1.5 microns or less, about 1.3 microns or less, or even about 1 micron or less.

The combination of the high adjacency and / or high homogeneity and / or reduced content of the metallic solvent / catalyst in the PCD on the one hand and the size distribution having on the other hand at least two peaks or modes, preferably at least three peaks or modes, It can result in a significant improvement in the wear resistance and other properties of the PCD.

In one embodiment, at least one of the plurality of ultrahard regions comprises a PCD material comprising diamond particles having a multi-modal size distribution. In some embodiments, the PCD material includes diamond particles having an average size of about 20 microns or less, about 10 microns or less, about 7 microns or less, or even about 5 microns or less. In one embodiment, the PCD material includes diamond particles having an average size of about 0.1 micron or more.

In one embodiment, the PCD material comprises diamond particles having a size distribution feature where at least 50 percent of the particles have an average size of greater than 5 microns and at least 20 percent of the particles have an average size in the range of 10 to 15 microns. .

The volume of ultrahard material included therein can be reduced or minimized, which is important because the ultrahard material can be expensive to manufacture and can be exposed to high tensile residual stresses.

In a further aspect, there is provided a rotary drill bit comprising an ultrahard insert as described above or described herein.

In another aspect, a ground perforator is provided that includes the ultrahard insert described above or described herein. In one embodiment, the ground perforator may be a rotary drill bit for drilling in rock, for example for extracting oil or gas.

Non-limiting embodiments will now be described with reference to the accompanying drawings.
1A is a schematic perspective view of one embodiment of an ultrahard insert.
FIG. 1B is a schematic longitudinal cross-sectional view taken along line AA of FIG. 1A.
2-8 are schematic perspective views of an embodiment of an ultrahard insert and (b) is a schematic longitudinal cross-sectional view taken along the AA line in each (a).
9 is a perspective view, as well as a partially exploded, perspective view of one embodiment of an ultrahard insert.
10 is a perspective view of the support and the clamp means in one embodiment of the ultrahard insert.
FIG. 11 is a schematic perspective view of one embodiment of a portion of a ground drill rotary drill bit comprising a plurality of ultra hard inserts. FIG.
Like reference numerals are used throughout the drawings to refer to like elements.

1A and 1B, one embodiment of the ultrahard insert 100 for a rotary ground perforator (not shown) includes a cutter end 110 having a peripheral cutter edge 120, the peripheral cutter edge At least a portion of 120 is defined by a plurality of alternating hard regions 122a, 122b, 122c and a plurality of edges 120a, 120b, 120c, 120d, 120e, 120f of superhard regions 124a, 124b, 124c. And the edges of the superhard regions 124a, 124b, 124c are spaced apart from each other and separated by the edges of the hard regions 122a, 122b, 122c. The hardness of each hard region 122a, 122b, 122c is 50% or less of the hardness of each superhard region 124a, 124b, 124c. The ultrahard insert includes a plurality of ultrahard structures 130a, 130b, 130c mounted to a plurality of respective recesses formed around the sintered carbide support 140, each of the superhard structures being formed at each of the cutter ends. Each surface is exposed at cutter end 110 to provide superhard regions 124a, 124b, 124c. Each of the superhard structures has respective edges that form the edges of each of the superhard regions 124a, 124b, 124c at the cutter end.

With reference to FIG. 2, one embodiment of the ultrahard insert 100 looks generally oval when viewed from above the cutter end 110, and has a pair of PCD structures lying on the elliptical long axis AA of the cutter end 110. 130a, 130b, each PCD structure providing respective superhard areas 124a, 124b on the cutter end 110.

3 and 4, one embodiment of the ultrahard insert 100 is a generally triangular having three rounded corners when viewed from above the cutter end 110, with each rounded corner having three PCD structures ( Each of 130a, 130b, 130c is disposed.

5A and 5B, one embodiment of the ultrahard insert 100 includes three spoke formations 150a, 150b, 150c projecting radially from the central region 160 of the cutter end, respectively. The spokes of each support each PCD structure 130a, 130b, 130c.

6A and 6B, one embodiment of the ultrahard insert 100 includes a ridge or boss portion 180 on the cutter end 110. The ridge or boss portion 180 can function as a chip in use. The ridge or boss portion 180 may be integrally formed with the support 140 or may be secured to the support by mechanical, brazing or gluing means (not shown).

7A and 7B, one embodiment of the ultrahard insert 100 includes a plurality of PCD structures 130a, 130b, 130c, each PCD structure having a respective exposure on the cutter end 110. Has a face. Clamp member 182 is secured to work surface 110 by pins, rivets, bolts, etc. 190, and lip 184 of clamp member 182 exposes each of the PCD structures 130a, 130b, 130c. Extends above faces 124a, 124b, and 124c. The lip 184 can help to secure the PCD structures 130a, 130b, 130c in place. In one embodiment clamp member 182 provides a rake face at cutter end 110.

8A and 8B, one embodiment of the ultrahard insert 100 includes a plurality of PCD structures 130a, 130b, 130c, each PCD structure surrounding from a ridge or boss portion 180. Each exposed cutting surface 124a, 124b, 124c rests on each rake face 186a, 186b, 186c suspended down to the cutter edge 120. In some embodiments, through holes are provided such that the hard insert 100 can be secured to a tool carrier (not shown), such as a ground drill bit, by pins, rivets, bolts, etc. 190. In one embodiment with reference to FIG. 10, each of the rake faces 186a, 186b, 186c are disposed at different angles with respect to each other, and each of the rake faces 186a, 186b, 186c is a respective PCD structure 130a, 130b. , 130c), with each visible marker that can be used to identify either or both of angles or grades.

Referring to FIG. 9, one embodiment of the ultrahard insert 100 includes a support assembly 200 further comprising a cutter support structure 210 and a base 220, the cutter support structure 210 being mechanical It can be fixed to the base by a locking mechanism. The locking mechanism is formed in at least one recess 220a, 220b, 220c formed in the base 220 or in the cutter support structure 210 or both, and the cutter support structure 210 or the base 220. It may include at least one cooperating tongue or protrusion 230.

Referring to FIG. 10, one embodiment of a portion of the ultrahard insert includes a support 140 and clamp means 142. PCD structures (not shown) may be clamped to the support 140 by clamp means 142.

Referring to FIG. 11, which is an embodiment of a drill bit 300 for ground and rock drilling, an ultrahard insert 100 according to the present invention is mounted to a carrier body 310 in a plurality of embodiments. The ultrahard insert 100 is mounted with one PCD structure that at least partially protrudes from the carrier.

The cutter insert can be secured to the support by various means including brazing, adhesive material, mechanical means (eg, interlocking with the support), or integrally bonded to the support during the stage of sintering of the PCD as conventionally. Can be. Preferably, the PCD structure is sintered and treated before being fixed to the support. This allows the PCD material to be prepared independently of the support on which it is finally fixed, thus eliminating certain constraints in material manufacture, such as the choice of solvent / catalyst form for diamond and whether the gap of the PCD contains fillers. Has the advantage.

Homogeneity or uniformity of PCD structures can be quantified by conducting statistical assessments using multiple micrographs of polished sections. The distribution of the filler phase, which can be easily distinguished from the distribution of the diamond phase using electron microscopy, can then be measured in a method similar to that disclosed in EP 0974566 (see WO 2007/110770). This method allows for statistical evaluation of the average thickness of the binder phase along several arbitrarily drawn lines through the microstructure. This binder thickness measurement is also referred to by those skilled in the art as "average free stroke". For two materials with similar overall composition or binder content and average diamond particle size, materials with thinner average thickness will tend to be more homogeneous, meaning that the binder is distributed on a more precise scale within the diamond phase. Also, the smaller the standard deviation of this measurement, the more homogeneous the structure. Large standard deviations mean that the binder thickness varies widely across the microstructure, i.e., the structure is not uniform but has widely different structure shapes.

Images used for image analysis should be obtained by scanning electron micrographs (SEM) taken using backscattered electron signals. Optical micrographs may not provide sufficient contrast. Since interparticle boundaries can be identified based on gray scale contrast, adequate contrast is important for the measurement of adjacency.

Proximity can be determined from SEM images by image analysis software. In particular, software under the trade name Analysis Pro from Soft Imaging System® GmbH (trademark of Olympus Soft Imaging Solutions GmbH) can be used. The software has a "Separate Grains" filter, and according to the operating manual, the filter gives satisfactory results only if the structure to be separated is a sealed structure. Therefore, it is important to fill all the holes before applying this filter. For example, a "Morph. Close" command may be used or may be helpful for obtaining from a "Fillhole" module. In addition to this filter, a "separator" is another powerful filter useful for particle separation. According to the operating manual, this separator can also be applied to color- and gray-value images.

In order to achieve the measurement of particle size, a method known as "equivalent circle diameter" is used, in which a circle of equal size in each individual microscope region is said to be the binder phase in the microstructure. Is identified. The collected distribution of these circles is then evaluated statistically. Exactly the same as in the mean free-stroke technique, the larger the standard deviation of this measurement, the less homogeneous the structure.

Diamond particle proximity (κ) is a measure of diamond-to-diamond contact and / or bonding and is calculated according to the following formula using data obtained from image analysis of polished sections of the PCD:

κ = 100 * [2 * (δ-β)] / [(2 * (δ-β)) + δ], where δ is the diamond perimeter and β is the binder perimeter.

Diamond circumference is the fraction of the diamond particle surface in contact with other diamond particles. For a given volume, this is measured as the total diamond-to-diamond contact area divided by the total diamond particle surface area. The binder perimeter is a fraction of the diamond particle surface that is not in contact with other diamond particles. In practice, the measurement of adjacency is made by image analysis of the polished section surface, the combined length of the line passing through all points lying on all diamond-to-diamond interfaces within the analyzed section to determine the diamond perimeter. And the same as for the binder perimeter.

(Yes)

Embodiments of the invention are described in more detail with reference to the following examples which are not intended to limit the invention.

Example 1

PCD discs were prepared. Raw diamond powders were prepared by mixing diamond particles from sources with different average sizes ranging from about 1 micron to about 15 microns. The average particle size of the mixed mix is about 10 micrometers. The mixed mix was formed into agglomerated mass and, as is well known in the art, sintered on cobalt-sintered sintered tungsten carbide (WC-Co) substrates at a pressure of about 6.8 GPa and a temperature of about 1,500 ° C. by an ultrahigh pressure furnace. It became.

After sintering, the sintered composite compact article was removed from the apparatus. The compact included a PCD layer integrally bonded onto the substrate. Microstructure data for the PCD is shown in Table 1. The diamond content of the PCD layer was about 92 volume percent, the remainder was cobalt and a small amount of precipitated phase, and cobalt was infiltrated from the substrate into the agglomerated diamond mass. Diamond particles in the PCD structure have a multimodal size distribution. Image analysis was used to analyze the homogeneity of its spatial distribution within the PCD as well as the in-growth of diamond particles. Particle ingrowth and contact can be expressed as diamond particle proximity, with an average proximity of PCD of 62.0 percent (± 1.9 percent). The mean mean free stroke of the PCD is about 0.74 (± 0.62) micrometers.

Average diamond
Particle size ^(a) ,
Micrometer PCD Diamond
content,
Volume percent filling
Average free stroke,
Micrometer Diamond particles
Proximity,
percent 11 (5.5) ^(b) 92 (1) 0.7 (0.6) 62 (2.0)

^(a) Average particle size is measured as equivalent circle diameter (ECD)

^(b) Figures in parentheses are the respective standard deviations.

The sintered carbide substrate is then removed from the composite compact by grinding, leaving an unsupported independent PCD disc. The PCD disc was ground to a thickness of about 2.2 micrometers and then cut into three segments by EDM, with the shape of each segment being substantially as shown in FIG. 3. All three PCD segments were then treated (leached) with acid to remove almost all cobalt solvent / catalyst material throughout the entire PCD structure, as is well known in the art.

The substrate support as substantially shown in FIG. 3 was processed from a sintered tungsten carbide body. Viewed from above, the substrate has a generally triangular shape with rounded corners. At each rounded corner the substrate is recessed, the size and shape of the recess being matched to accommodate the PCD segment, which was then brazed in the recess.

Claims (11)

Ultra-hard inserts for rotary ground drills,
A cutter end having a peripheral cutter edge, wherein at least a portion of the peripheral cutter edge is formed by a plurality of edges of a plurality of alternating hard and superhard regions, the edges of the superhard regions being spaced apart from each other and An ultrahard insert, separated by an edge, wherein the hardness of each hard zone is 50% or less of the hardness of each superhard zone. The ridge or boss of claim 1, wherein the cutter end includes a hard center region spaced from a peripheral cutter edge, the hard center region operable to deflect chips formed of material that is punctured or exploded from the cutter end. Ultra hard insert with a part. The hard insert of claim 1, wherein the at least one superhard region has an identification marker. The insert according to any one of the preceding claims, comprising a plurality of spoke formations projecting radially outwardly, each spoke comprising an ultrahard structure. 5. The ultrahard insert according to claim 1, wherein at least one or each of the at least one superhard region has sides that generally converge or generally diverge when viewed in plan view of the cutter end. 6. The hard insert according to any one of claims 1 to 5, wherein the Vickers hardness of each superhard region is at least 40 GPa. 8. The ultrahard insert according to claim 1, wherein at least one or each of the ultrahard regions comprises a PCD material. 8. The superhard insert of claim 1, wherein at least one of the plurality of superhard regions comprises a PCD material comprising diamond particles having an average diamond particle adjacency of at least about 60.5 percent. The superhard insert of claim 1, wherein at least one of the plurality of superhard regions comprises a PCD material having an interstitial mean free path of at least 0.05 microns and at most 1 micron. Rotary drill bit comprising an ultrahard insert according to any one of the preceding claims. A ground drilling machine comprising the rotary drill bit according to claim 10.

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