WO2014139889A2 - Extrémité super-dure et pic la comprenant - Google Patents

Extrémité super-dure et pic la comprenant Download PDF

Info

Publication number
WO2014139889A2
WO2014139889A2 PCT/EP2014/054458 EP2014054458W WO2014139889A2 WO 2014139889 A2 WO2014139889 A2 WO 2014139889A2 EP 2014054458 W EP2014054458 W EP 2014054458W WO 2014139889 A2 WO2014139889 A2 WO 2014139889A2
Authority
WO
WIPO (PCT)
Prior art keywords
strike
tip
apex
super
strike tip
Prior art date
Application number
PCT/EP2014/054458
Other languages
English (en)
Other versions
WO2014139889A3 (fr
Inventor
Robert Fries
Frank Friedrich Lachmann
Bernd Heinrich Ries
Original Assignee
Element Six Abrasives S.A.
Element Six Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Element Six Abrasives S.A., Element Six Gmbh filed Critical Element Six Abrasives S.A.
Publication of WO2014139889A2 publication Critical patent/WO2014139889A2/fr
Publication of WO2014139889A3 publication Critical patent/WO2014139889A3/fr

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C35/00—Details of, or accessories for, machines for slitting or completely freeing the mineral from the seam, not provided for in groups E21C25/00 - E21C33/00, E21C37/00 or E21C39/00
    • E21C35/18—Mining picks; Holders therefor
    • E21C35/183—Mining picks; Holders therefor with inserts or layers of wear-resisting material
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C35/00—Details of, or accessories for, machines for slitting or completely freeing the mineral from the seam, not provided for in groups E21C25/00 - E21C33/00, E21C37/00 or E21C39/00
    • E21C35/18—Mining picks; Holders therefor
    • E21C35/183—Mining picks; Holders therefor with inserts or layers of wear-resisting material
    • E21C35/1835—Chemical composition or specific material
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C35/00—Details of, or accessories for, machines for slitting or completely freeing the mineral from the seam, not provided for in groups E21C25/00 - E21C33/00, E21C37/00 or E21C39/00
    • E21C35/18—Mining picks; Holders therefor
    • E21C35/183—Mining picks; Holders therefor with inserts or layers of wear-resisting material
    • E21C35/1837—Mining picks; Holders therefor with inserts or layers of wear-resisting material characterised by the shape

Definitions

  • This disclosure relates generally to super-hard strike tips for pick tools and pick tools comprising same, particularly but not exclusively for road milling, mining or drilling into the earth.
  • United States patent application publication number 2009005121 1 discloses a high impact resistant tool comprising a super-hard material bonded to a cemented metal carbide substrate at a non-planar interface. At the interface, the substrate has a tapered surface starting from a cylindrical rim of the substrate and ending at an elevated flatted central region formed in the substrate.
  • the super-hard material has a pointed geometry with a sharp apex having 1.27 to 3.175 millimetre radius and a 2.45 to 12.7 millimetre thickness from the apex to the flatted central region of the substrate.
  • the substantially pointed geometry may comprise a side which forms a 35 to 55 degree angle with a central axis of the tool.
  • strike tips having a relatively sharper, more pointed apex are less likely to fracture than strike tips having a blunter apex because the latter tend to penetrate substantially less into the body being degraded, thereby providing little buttress support to the diamond substrate and causing the super-hard material to fail in shear/bending at a much lower load with larger surface area. Therefore, it would expected that the blunter tools tend to break at much lower impact energies than sharper tools, which is believed to be due to the distribution of the load across a greater surface area in the sharper tools. There is a need for a pick tool having high resistance to wear and fracture.
  • a strike tip for a pick tool comprising a strike structure joined to a substrate at an interface boundary, the strike structure comprising super-hard material and the substrate comprising carbide material; the strike structure having a convex strike end opposite the interface boundary, the strike end including an apex and defining an included angle between opposite sides of the apex, the included angle being at least about 100 degrees and at most about 120 degrees; the apex having a radius of curvature in a longitudinal plane of at least 3.2 millimetres or at least 3.3 millimetres.
  • the radius of curvature of the apex is as viewed in a longitudinal cross section plane passing through the outermost point or points of the apex and the interface boundary opposite the corresponding point or points of the apex.
  • the radius of curvature may also be evident from certain side views of the strike tip (or from any side view if the area of the strike end including the apex has the shape of a spheric section).
  • the radius of curvature of the apex may be at most about 6 millimetres or at most about 4 millimetres. In other example arrangements, the radius of curvature may be greater than 6 millimetres, or even very large. In some example arrangements, the radius of curvature may be sufficiently great that an area of the strike end including the apex may be substantially planar (as the radius of curvature tends to infinity, the apex will tend to become flatter, more planar).
  • the included angle may be at least about 105 degrees and or at most about 1 15 degrees. In a particular example, the angle may be about 1 10 degrees. In some example arrangements, the included angle may be greater than 1 10 degrees.
  • an area of the strike end comprising the apex may having the general shape of a spherically blunted cone, or the area may be generally chisel-shaped.
  • the strike end may include a cone surface, the included angle being a cone angle defined by the cone surface.
  • the strike end may include a plurality of cone surfaces, each concentric with the apex and having a different respective cone angle, the included angle being the cone angle of the innermost cone surface.
  • the strike end comprises a pair of convergent planar surface areas on opposite sides of the apex, the planar surfaces defining the included angle between them.
  • the super-hard material may comprise or consist of synthetic or natural diamond, polycrystalline diamond (PCD) material, cubic boron nitride (cBN), polycrystalline cubic boron nitride (PCBN) material and or silicon carbide bonded diamond material, for example.
  • the strike structure may comprise PCD material comprising diamond grains having a mean size of at least about 15 microns.
  • the PCD may comprise diamond grains having a mean size of at most about 100 microns or at most about 50 microns.
  • the size distribution of the diamond grains used as raw material for the PCD material may be multi-modal, and or the size distribution of the inter-grown diamond grains comprised in the PCD material may be multi-modal (the latter size distribution may be measured by means of image analysis of a polished surface of the PCD material).
  • the super-hard material may comprise PCD material, at least a region of which is coterminous with the strike end and includes solvent / catalyst material for diamond, the amount of the solvent / catalyst material being more than 5 weight per cent or at least 10 per cent of the PCD material.
  • the region may extend to a depth of at least 100 microns from the apex.
  • the PCD material may comprise more than 5 weight per cent or at least about 10 weight per cent solvent / catalyst material throughout substantially the entire volume of the super-hard material.
  • the content of solvent / catalyst material comprised in the PCD material may vary within a range from at least 5 weight per cent to about 20 weight per cent or about 10 weight per cent of the PCD material.
  • the strike tip may comprise a layer structure attached to the strike end, the layer structure being substantially softer than the super-hard material coterminous with the strike end.
  • the interface boundary may be substantially planar or non-planar, and may include a depression in the substrate and or a projection from the substrate.
  • the interface boundary may include a depression in the substrate opposite the apex.
  • the interface boundary may be generally dome-shaped, defined by a convex proximate end boundary of the substrate.
  • the interface boundary may include a generally dome-shaped central area having a radius of curvature in the longitudinal plane of at least 1 millimetre, at least 2 millimetres or at least 5 millimetres. In some examples, the radius of curvature of the interface boundary may be at most about 20 millimetres.
  • the proximate boundary end of the substrate may have a generally dome-shaped central area at least partly surrounded by a peripheral shelf, in which the domed-shaped area may include a central depression, or need not include a central depression.
  • the thickness of the strike structure between the apex (measured from the outermost point or points of the apex) and the opposite interface boundary may be at least 2.5 millimetres. In some examples, the thickness may be at most about 10 millimetres.
  • the apex may be spaced apart from an opposite end of the strike tip by at least about 8 millimetres. In some examples, the apex may be spaced apart from the opposite end of the strike tip by at most about 20 millimetres or at most about 15 millimetres.
  • the substrate may comprise cemented tungsten carbide material including at least 5 weight per cent and at most about 10 weight per cent binder material comprising cobalt. In some example arrangements, the substrate may comprise cobalt-cemented tungsten carbide.
  • the super-hard material may be formed joined to the substrate, by which is mean that the super-hard material is produced (for example sintered) in the same general step in which the super-hard structure becomes joined to the substrate.
  • the substrate may comprise cemented tungsten carbide material including at least about 5 weight per cent and at most about 10 weight per cent or at most about 8 weight per cent binder material, which may comprise cobalt (as measured prior to subjecting the substrate to any high-pressure, high temperature condition at which the super-hard structure may be produced; the actual binder content after such treatment is likely to be somewhat lower).
  • the cemented carbide material may have Rockwell hardness "A" of at least about 88 HRa; transverse rupture strength of at least about 2,500 megapascals; and or magnetic saturation of at least about 8 G.cm3/g (Gauss times cubic centimetre per gram) and at most about 16 G.cm3/g (Gauss times cubic centimetre per gram) or at most about 13 G.cm3/g (Gauss times cubic centimetre per gram) and coercivity of at least about 6 kA m (kiloampere per metre) and at most about 14 kA m (kiloampere per metre).
  • Cemented carbide having relatively low binder content is likely to provide enhanced stiffness and support for the tip in use, which may help reduce the risk of fracture, and is likely to exhibit good wear resistance.
  • the strike structure may consist substantially of a single grade of PCD or it may comprise a plurality of PCD grades arranged in various ways, such as in layered or lamination arrangements.
  • the strike structure may comprise a plurality of strata arranged so that adjacent strata comprise different PCD grades, adjacent strata being directly bonded to each other by inter-growth of diamond grains.
  • the substrate may comprise an intermediate volume and a core volume comprising cemented carbide material, the intermediate volume being coterminous with the interface boundary and with the core volume, the intermediate volume being greater than the volume of the strike structure and comprising an intermediate material having a mean Young's modulus in the range of about 60 per cent and 90 per cent of the Young's modulus of the super-hard material.
  • the pick tool may be for degrading road paving or rock formations in mining operations, for example, and the pick tool may be mounted onto a carrier such as a drum or a fixture joined to a drum for a road milling or mining apparatus.
  • the pick tool may be for a drill bit for drilling into the earth.
  • a pick tool assembly comprising a strike tip according to this disclosure, in assembled or non-assembled form.
  • the pick tool assembly may be for road milling, mining or drilling into the earth.
  • the assembly may comprise the strike tip joined to a proximate end of a support body.
  • the support body may be generally columnar and or cylindrical in shape and the proximate end may be generally frusto-conical.
  • the volume of the support body may be at least about 15 cubic centimetres or at least about 25 cubic centimetres. While wishing not to be bound by a particular theory, support bodies having relatively large volume will likely enhance the robustness of the pick and enhance its overall resistance to abrasive wear.
  • the support body may comprise cemented tungsten carbide, ceramic material, silicon carbide cemented diamond material or super-hard material, and the base may comprise steel.
  • the support material may have Rockwell hardness "A" of at least about 90 HRa and transverse rupture strength of at least about 2,500 megapascals.
  • the support body may comprise or consist of cemented tungsten carbide material having magnetic saturation of at least about 7 G.cm3/g (Gauss times cubic centimetre per gram) and at most about 1 1 G.cm3/g (Gauss times cubic centimetre per gram) and coercivity of at least about 9 kA/m (kiloampere per metre) and at most about 14 kA m (kiloampere per metre).
  • the support body may comprise or consist of cemented carbide material, which may comprise tungsten carbide grains and at least about 5 weight per cent and at most about 10 weight per cent or at most about 8 weight per cent binder material, which may comprise cobalt.
  • the tungsten carbide grains may have a mean size of at most about 6 microns, at most about 5 microns or at most about 3 microns.
  • the mean size of the tungsten carbide grains may be at least about 1 micron or at least about 2 microns.
  • the support body may be mounted or mountable onto or into a base, which may comprise steel.
  • the support body may be shrink or press fitted into a bore provided in the base, and or the support body may be bonded to the base, such as by brazing.
  • the support body may comprise or consist of a grade of cemented carbide or other material (for example ceramic material or super-hard material, or composite material comprising grains of super-hard material dispersed within a matrix comprising ceramic material, such as silicon carbide) that is technically difficult and or costly to attach by other means, such as brazing.
  • cemented carbide material for example ceramic material or super-hard material, or composite material comprising grains of super-hard material dispersed within a matrix comprising ceramic material, such as silicon carbide
  • grades of cemented tungsten carbide material that are likely to be relatively highly resistant to abrasive wear will likely comprise relatively high content of tungsten carbide grains and correspondingly lower content of cement material such as cobalt, which will likely render it more difficult to attach by brazing.
  • Fig. 1A shows a schematic side view if an example strike tip
  • Fig. 1 B shows a schematic longitudinal cross section view of the example strike tip
  • Fig. 2 shows a schematic perspective view of an example pick tool
  • Fig. 3 shows a schematic perspective view of an example road milling drum, to which are attached a plurality of pick tools;
  • an example strike tip 100 comprises a strike structure 1 10 joined to a cemented carbide substrate 120 at an interface boundary 122 between the substrate 120 and the strike structure 1 10.
  • the strike structure 1 10 consists of PCD material and has a strike end 1 12 in the general form of a blunted cone that includes a spherically blunted apex 1 14, and which defines an included angle A in the range of 104 degrees to 1 16 degrees between points on opposite sides of the apex 1 14.
  • the apex 1 14 is formed by a substantially spheric section having a radius of curvature R in the range of 3.5 to about 4 millimetres (as viewed in a longitudinal plane parallel to a longitudinal axis L passing through the apex 1 14 and the interface boundary 122 opposite the apex 1 14).
  • the radius of curvature R is evident from a side view of the strike tip 100 as shown in Fig. 1A.
  • the conical surface area of the strike end 1 12 is inclined at an angle A/2 of about 35 degrees with respect to a plane tangent to a peripheral side surface of the strike tip 100.
  • the interface boundary 122 is generally dome-shaped (a spheric section) and defined by a spherically convex proximate end of the substrate 120 having a radius of curvature in the longitudinal plane of about 9 millimetres.
  • the thickness T of the PCD strike structure between the apex 1 14 and the interface boundary 122 opposite the apex 1 14 is about 4 millimetres.
  • the overall height H of the strike tip 100 between the apex 1 14 and a distal end of the substrate 120 opposite the apex 1 14 is in the range of about 8.8 to about 9.5 millimetres (as used herein, heights being longitudinal components of distances).
  • the height H1 of the side of the substrate 120 from its distal end to the interface boundary 122, as visible at the side of the strike tip 100, is about 2.5 millimetres.
  • the height H2 of the PCD strike structure 1 10 from the interface boundary 122, as evident at the side, to the outer circumferential edge of the conical area of the strike end 1 12, is about 3 millimetres.
  • the height H3 from the circumferential edge of the conical area of the strike end 1 12 to the circular boundary between the conical area of the strike end 1 12 and the spheric section comprising the apex 1 14, is about 3.4 millimetres.
  • the height H4 of the spheric section to the outermost point of the apex 1 14 is about 0.6 millimetres.
  • the volume of the PCD strike structure 1 10 is about 280.7 cubic millimetres and the volume of the substrate is about 476 cubic millimetres.
  • the PCD material comprises about 82 weight per cent substantially inter-gown diamond grains and about 18 weight per cent filler material disposed in the interstitial regions between the diamond grains, the filler material comprising cobalt.
  • the diamond grains have a mean size of about 20 microns.
  • the substrate 120 comprises cobalt-cemented tungsten carbide material comprising about 92 weight per cent tungsten carbide (WC) grains and about 8 weight per cent cobalt (Co).
  • the magnetic saturation of the cemented carbide material is in the range from about 132 to about 136 in units of 0.1 microtesla times cubic metre per kilogram ⁇ T.m3/kg) or, in different units, about 10.5 to about 12.8 Gauss times cubic centimetre per gram (G.cm3/g), and the magnetic coercivity is in the range from about 7.2 to about 8.8 kiloamperes per metre (kA/m) or about 90 to about 1 10 Oersted (Oe).
  • the Rockwell "A” hardness of the cemented carbide material is about 88.7 HRa, the transverse rupture strength is about 2,800 megapascals (MPa), the fracture toughness is about 14.6 megapascals (MPa) and the Young's modulus is about 600 megapascals (MPa).
  • the volume of the PCD strike structure 1 10 may be at least 70 per cent and at most 150 per cent of the volume of the substrate 120.
  • an example pick tool arrangement 200 comprises a strike tip 100 joined to a frusto-conical proximate end of a generally columnar support body 210 by means of braze material.
  • the support body 210 comprises a substantially cylindrically shaped insertion shaft (not visible in Fig. 2), which is shrink fit into a bore formed into a holder base 220.
  • the holder base 220 comprises a shank 230 for mounting the pick 200 onto a drum (an example of which is shown schematically in Fig. 3) via a coupling mechanism that may be referred to as a "base block" (not shown).
  • the shank 230 is not aligned with the insertion shaft of the support body 210, and the volume of the support body 210 is about 30 cubic centimetres and its length is about 6.8 centimetres.
  • the support body 210 may comprise a cemented carbide material comprising grains of tungsten carbide having a mean size of at about 2.5 microns to about 3 microns, and at most about 10 weight per cent of metal binder material, such as cobalt (Co).
  • a cemented carbide material comprising grains of tungsten carbide having a mean size of at about 2.5 microns to about 3 microns, and at most about 10 weight per cent of metal binder material, such as cobalt (Co).
  • edges and corners may be radiused or chamfered, and the edge of the bore may be provided with a radius or chamfer to reduce the risk of stress-related cracks arising.
  • the pick tool 200 will be driven in the generally forward direction F, such that the strike end 1 12 of the strike tip 100 is capable of striking a body or formation to be broken or otherwise mechanically degraded.
  • a plurality of pick tools 200 may be mounted onto a drum 300 suitable for road milling or mining.
  • the drum 300 will need to be coupled to and driven by a vehicle (not shown) such that the drum 300 will be driven to rotate and the picks 200 repeatedly to strike the asphalt or rock, for example, as the drum 300 rotates in the forward direction F.
  • the picks 200 may be arranged such that each strike tip does not strike the body directly with the top of the apex, but somewhat obliquely to achieve a digging action in which the body is locally broken up by the strike tip. Repeated impact of the strike tip against hard material is likely to result in the abrasive wear and or fracture of the strike tip and or other parts of the pick.
  • Example methods for making a strike tip comprising a PCD strike structure joined to a substrate will now be described.
  • a strike tip may be made by placing an aggregation comprising a plurality of diamond grains onto a cemented carbide substrate and subjecting the resulting assembly in the presence of a catalyst material for diamond to an ultra-high pressure and high temperature at which diamond is more thermodynamically stable than graphite, to sinter together the diamond grains and form a PCD structure joined to the substrate body.
  • Binder material within the cemented carbide substrate body may provide a source of the solvent / catalyst material, such as cobalt, iron or nickel, or mixtures or alloys including any of these.
  • a source of solvent / catalyst material may be provided within the aggregation of diamond grains, in the form of admixed powder or deposits on the diamond grains, for example.
  • a source of solvent / catalyst material may be provided proximate a boundary of the aggregation other than the boundary between the aggregation and the substrate body, for example adjacent a boundary of the aggregation that will correspond to the strike end of the sintered PCD structure.
  • the aggregation may comprise substantially loose diamond grains, or diamond grains held together by a binder material.
  • the aggregation may be in the form of granules, discs, wafers or sheets, and may contain catalyst material for diamond and or additives for reducing abnormal diamond grain growth, for example, or the aggregation may be substantially free of catalyst material or additives.
  • aggregations in the form of sheets comprising a plurality of diamond grains held together by a binder material may be provided.
  • the sheets may be made by a method such as extrusion or tape casting, in which slurries comprising diamond grains having respective size distributions suitable for making the desired respective PCD grades, and a binder material is spread onto a surface and allowed to dry.
  • Other methods for making diamond-containing sheets may also be used, such as described in United States patents numbers 5,766,394 and 6,446,740.
  • Alternative methods for depositing diamond-bearing layers include spraying methods, such as thermal spraying.
  • the binder material may comprise a water-based organic binder such as methyl cellulose or polyethylene glycol (PEG) and different sheets comprising diamond grains having different size distributions, diamond content and or additives may be provided.
  • sheets comprising diamond grains having a mean size in the range from about 15 microns to about 80 microns may be provided.
  • Discs may be cut from the sheet or the sheet may be fragmented.
  • the sheets may also contain catalyst material for diamond, such as cobalt, and or precursor material for the catalyst material, and or additives for inhibiting abnormal growth of the diamond grains or enhancing the properties of the PCD material.
  • the sheets may contain about 0.5 weight per cent to about 5 weight per cent of vanadium carbide, chromium carbide or tungsten carbide.
  • the aggregation of diamond grains may include precursor material for catalyst material.
  • the aggregation may include metal carbonate precursor material, in particular metal carbonate crystals
  • the method may include converting the binder precursor material to the corresponding metal oxide (for example, by pyrolysis or decomposition), admixing the metal oxide based binder precursor material with a mass of diamond particles, and milling the mixture to produce metal oxide precursor material dispersed over the surfaces of the diamond particles.
  • the metal carbonate crystals may be selected from cobalt carbonate, nickel carbonate, copper carbonate and the like, in particular cobalt carbonate.
  • the catalyst precursor material may be milled until the mean particle size of the metal oxide is in the range from about 5 nm to about 200 nm.
  • the metal oxide may be reduced to a metal dispersion, for example in a vacuum in the presence of carbon and/or by hydrogen reduction.
  • the controlled pyrolysis of a metal carbonate, such as cobalt carbonate crystals provides a method for producing the corresponding metal oxide, for example cobalt oxide (Co304), which can be reduced to form cobalt metal dispersions.
  • the reduction of the oxide may be carried out in a vacuum in the presence of carbon and/or by hydrogen reduction.
  • a substrate body comprising cemented carbide in which the cement or binder material comprises a catalyst material for diamond, such as cobalt, may be provided.
  • the substrate body may have a non-planar or a substantially planar proximate end on which the PCD structure is to be formed.
  • the proximate end may be configured to reduce or at least modify residual stress within the PCD.
  • a cup having a generally conical internal surface may be provided for use in assembling the diamond aggregation, which may be in the form of an assembly of diamond- containing sheets, onto the substrate body. The aggregation may be placed into the cup and arranged to fit substantially conformally against the internal surface.
  • the substrate body may then be inserted into the cup with the proximate end going in first and pushed against the aggregation of diamond grains.
  • the substrate body may be firmly held against the aggregation by means of a second cup placed over it and inter-engaging or joining with the first cup to form a pre-sinter assembly.
  • the pre-sinter assembly can be placed into a capsule for an ultra-high pressure press and subjected to an ultra-high pressure of at least about 5.5 gigapascals (GPa) and a temperature of at least about 1 ,300 degrees Celsius to sinter the diamond grains and form a construction comprising a PCD structure sintered onto the substrate body.
  • GPa gigapascals
  • the binder material within the support body melts and infiltrates the aggregation of diamond grains.
  • the presence of the molten catalyst material from the support body and or from a source provided within the aggregation will promote the sintering of the diamond grains by intergrowth with each other to form a PCD structure.
  • the diamond grains may be sintered at a pressure of at least about 6 gigapascals or at least about 7 gigapascals. It is likely that strike tips comprising PCD strike structures sintered at such relatively high pressures may display enhanced robustness and working life in use.
  • abrasive wear of the strike tip is relatively less important because super-hard material is relatively abrasion resistant and the most likely failure mode will be fracture, since super-hard material tends to be relatively prone to fracture.
  • repeated impact on the strike tip as in road milling or mining is likely to induce fatigue-related crack propagation and fracture as cracks are likely to increase in size with each impact until a crack progresses to a surface of the strike tip and a portion of the strike tip breaks off. For at least this reason, the likely mean working life of a type of strike tip may be indicated by means of a laboratory test involving cyclic impact of a strike tip onto a hard body as well as by monotonic loading of the strike tip.
  • Disclosed strike tips and picks comprising them may have the aspect of good working life, at least because of reduced risk of fracture or substantially delayed fracture. They are also likely to be relatively easier and efficient to manufacture at least because the incidence of sinter defects is likely to be reduced. While wanting not to be limited by a particular theory, this may be due to the likelihood of more homogeneous infiltration of catalyst material from the substrate through the aggregation of diamond grains to the apex during the sintering step, in which the super-hard strike structure is sintered. In addition, the risk of substantial deformation of the blunter apex during the sinter step may be expected to be reduced. Blunter strike tips may also be expected to be less prone to accidental breakage during handling in the field.
  • the force required per pick to break the body or formation being degraded would be higher if the strike tips are blunter and power consumption may be slightly greater.
  • the forces and power consumption are expected to be substantially less or at least no greater than required when using conventional cemented carbide strike tips, which are prone to substantial blunting in use as a result of their substantially lower wear resistance than super-hard strike tips.
  • strike tips in which the strike structure comprises or substantially consists of PCD material comprising more than 5 weight per cent filler material proximate or adjacent a strike surface of the strike end are likely to exhibit enhanced fracture toughness.
  • PCD having relatively higher content of filler material with respect to diamond tends to have reduced wear resistance If the included angle is substantially less than about 100 degrees, then the impact resistance if the tip may be inadequate, and if the included angle is substantially greater than about 120 degrees, then the tip may not penetrate sufficiently deeply into a body being degraded.
  • PCD having relatively higher content of filler material with respect to diamond tends to have reduced wear resistance
  • the included angle is substantially less than about 100 degrees, then the impact resistance if the tip may be inadequate, and if the included angle is substantially greater than about 120 degrees, then the tip may not penetrate sufficiently deeply into a body being degraded.
  • a non-limiting example is described in detail below.
  • the control tip comprised a PCD strike structure, the strike end of which had the general shape of a spherically blunted cone and the apex of which had a radius of curvature of 2.4 millimetres.
  • the monotonic loading test involved subjecting each strike tip to an increasing load up to a maximum of 100 kilonewtons (kN) or until it fractured.
  • the load was applied by driving a load element vertically down onto the strike tip, the load element comprising a PCD structure having a substantially planar surface.
  • the strike tip was mounted in a jig and held canted at an angle of 32 degrees to the vertical and a small, substantially flat contact area of about 2 to 3 square millimetres was ground onto the tip proximate the apex, where there load element would impinge the tip.
  • the strike tip held securely by the jig was positioned within a Universal Tester (Instron 5500RTM) and the load element was driven down at a constant advance rate of 0.1 millimetres per minute (mm/min) until one of the following failure criteria was met: complete failure of the shaped cutter, failure of the PCD load element or the maximum load was reached. The first of these is expected to provide a more reasonable indication of the strength of the strike tip than the other two.
  • the failure load was divided by the contact area in order to give an indication of contact stress, which is a measure of the combined effect of several aspects including the strength of the strike structure, residual stresses within the strike tip and geometrical effects arising from the cant angle.
  • Synthetic and natural diamond, polycrystalline diamond (PCD), cubic boron nitride (cBN) and polycrystalline cBN (PCBN) material are examples of super-hard materials.
  • synthetic diamond which is also called man-made diamond, is diamond material that has been manufactured.
  • polycrystalline diamond (PCD) material comprises an aggregation of a plurality of diamond grains, a substantial portion of which are directly inter-bonded with each other and in which the content of diamond is at least about 80 volume per cent of the material. Interstices between the diamond grains may be at least partly filled with a filler material that may comprise catalyst material for synthetic diamond, or they may be substantially empty.
  • a catalyst material (which may also be referred to a solvent / catalyst material) for synthetic diamond is capable of promoting the growth of synthetic diamond grains and or the direct inter-growth of synthetic or natural diamond grains at a temperature and pressure at which synthetic or natural diamond is thermodynamically stable.
  • catalyst materials for diamond are Fe, Ni, Co and Mn, and certain alloys including these.
  • Bodies comprising PCD material may comprise at least a region from which catalyst material has been removed from the interstices, leaving interstitial voids between the diamond grains.
  • a PCD grade is a variant of PCD material characterised in terms of the volume content and or size of diamond grains, the volume content of interstitial regions between the diamond grains and composition of material that may be present within the interstitial regions.
  • Different PCD grades may have different microstructure and different mechanical properties, such as elastic (or Young's) modulus E, modulus of elasticity, transverse rupture strength (TRS), toughness (such as so- called K1 C toughness), hardness, density and coefficient of thermal expansion (CTE).
  • Different PCD grades may also perform differently in use. For example, the wear rate and fracture resistance of different PCD grades may be different.
  • PCBN material comprises grains of cubic boron nitride (cBN) dispersed within a matrix comprising metal or ceramic material.
  • super-hard materials include certain composite materials comprising diamond or cBN grains held together by a matrix comprising ceramic material, such as silicon carbide (SiC), or cemented carbide material, such as Co- bonded WC material (for example, as described in United States patents numbers 5,453,105 or 6,919,040).
  • SiC-bonded diamond materials may comprise at least about 30 volume per cent diamond grains dispersed in a SiC matrix (which may contain a minor amount of Si in a form other than SiC). Examples of SiC-bonded diamond materials are described in United States patents numbers 7,008,672; 6,709,747; 6,179,886; 6,447,852; and International Application publication number WO2009/013713).
  • the volume of the material within which the content is measured is to be sufficiently large that the measurement is substantially representative of the bulk characteristics of the material.
  • the content of the filler material in terms of volume or weight per cent of the PCD material should be measured over a volume of the PCD material that is at least several times the volume of the diamond grains so that the mean ratio of filler material to diamond material is a substantially true representation of that within a bulk sample of the PCD material (of the same grade).
  • a shrink fit is a kind of interference fit between components achieved by a relative size change in at least one of the components (the shape may also change somewhat). This is usually achieved by heating or cooling one component before assembly and allowing it to return to the ambient temperature after assembly.
  • Shrink-fitting is understood to be contrasted with press-fitting, in which a component is forced into a bore or recess within another component, which may involve generating substantial frictional stress between the components.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Earth Drilling (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)

Abstract

La présente invention concerne une extrémité de frappe pour un pic, comprenant une structure de frappe jointe à un substrat au niveau d'une interface formant limite, la structure de frappe comprenant un matériau super-dur et le substrat comprenant un matériau à base de carbure ; la structure de frappe présente une extrémité de frappe convexe à l'opposé de l'interface formant limite, l'extrémité de frappe comprenant un sommet définissant un angle inclus entre les côtés opposés du sommet, l'angle inclus faisant au moins 0 degré et au maximum 120 degrés ; le sommet présente un rayon de courbure dans un plan longitudinal d'au moins 3,2 millimètres.
PCT/EP2014/054458 2013-03-12 2014-03-07 Extrémité super-dure et pic la comprenant WO2014139889A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201361777071P 2013-03-12 2013-03-12
GB1304408.6 2013-03-12
GBGB1304408.6A GB201304408D0 (en) 2013-03-12 2013-03-12 Super-hard tip and pick tool comprising same
US61/777,071 2013-03-12

Publications (2)

Publication Number Publication Date
WO2014139889A2 true WO2014139889A2 (fr) 2014-09-18
WO2014139889A3 WO2014139889A3 (fr) 2015-05-28

Family

ID=48189758

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2014/054458 WO2014139889A2 (fr) 2013-03-12 2014-03-07 Extrémité super-dure et pic la comprenant

Country Status (2)

Country Link
GB (2) GB201304408D0 (fr)
WO (1) WO2014139889A2 (fr)

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5890552A (en) * 1992-01-31 1999-04-06 Baker Hughes Incorporated Superabrasive-tipped inserts for earth-boring drill bits
US6315065B1 (en) * 1999-04-16 2001-11-13 Smith International, Inc. Drill bit inserts with interruption in gradient of properties
US8007051B2 (en) * 2006-08-11 2011-08-30 Schlumberger Technology Corporation Shank assembly
WO2008105915A2 (fr) * 2006-08-11 2008-09-04 Hall David R Matériau extra-dur pointu et épais
US7648210B2 (en) * 2006-08-11 2010-01-19 Hall David R Pick with an interlocked bolster
US7637574B2 (en) * 2006-08-11 2009-12-29 Hall David R Pick assembly
US20080035389A1 (en) * 2006-08-11 2008-02-14 Hall David R Roof Mining Drill Bit
EP2053198A1 (fr) * 2007-10-22 2009-04-29 Element Six (Production) (Pty) Ltd. Corps à pointe
US8540037B2 (en) * 2008-04-30 2013-09-24 Schlumberger Technology Corporation Layered polycrystalline diamond
GB2490795B (en) * 2011-05-10 2015-11-04 Element Six Abrasives Sa Pick tool
GB201113013D0 (en) * 2011-07-28 2011-09-14 Element Six Abrasive Sa Tip for a pick tool
GB201118739D0 (en) * 2011-10-31 2011-12-14 Element Six Abrasives Sa Tip for a pick tool, method of making same and pick tool comprising same
GB201201120D0 (en) * 2012-01-24 2012-03-07 Element Six Abrasives Sa Pick tool and assembly comprising same

Also Published As

Publication number Publication date
GB2514220A (en) 2014-11-19
GB201304408D0 (en) 2013-04-24
GB201404042D0 (en) 2014-04-23
WO2014139889A3 (fr) 2015-05-28

Similar Documents

Publication Publication Date Title
EP2795062B1 (fr) Pointe super dure pour un outil d'extraction et outil d'extraction la comprenant
EP2773839B1 (fr) Pointe pour un outil de pic, son procédé de réalisation et outil de pic la comprenant
EP2900917B1 (fr) Tête de percussion pour un marteau-piqueur comprenant une surface apex plane
EP2815029B1 (fr) Outil d'extraction et procédé d'utilisation de cet outil
US9334731B2 (en) Pick tool and assembly comprising same
EP2707573B1 (fr) Pointe pour outil de dégradation et outil la comprenant
GB2506718A (en) Multilayered polycrystalline diamond structure
US20200277854A1 (en) Strike tip for a pick tool
WO2014139889A2 (fr) Extrémité super-dure et pic la comprenant

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14709240

Country of ref document: EP

Kind code of ref document: A2

122 Ep: pct application non-entry in european phase

Ref document number: 14709240

Country of ref document: EP

Kind code of ref document: A2