EP0738823B1 - Elément de coupe avec une surface en matériaux extra-dur - Google Patents

Elément de coupe avec une surface en matériaux extra-dur Download PDF

Info

Publication number
EP0738823B1
EP0738823B1 EP96302709A EP96302709A EP0738823B1 EP 0738823 B1 EP0738823 B1 EP 0738823B1 EP 96302709 A EP96302709 A EP 96302709A EP 96302709 A EP96302709 A EP 96302709A EP 0738823 B1 EP0738823 B1 EP 0738823B1
Authority
EP
European Patent Office
Prior art keywords
ribs
element according
preform element
facing table
point
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
EP96302709A
Other languages
German (de)
English (en)
Other versions
EP0738823A2 (fr
EP0738823A3 (fr
Inventor
Terry R. Matthias
Alex Newton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Camco Drilling Group Ltd
Original Assignee
Camco Drilling Group Ltd
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 Camco Drilling Group Ltd filed Critical Camco Drilling Group Ltd
Publication of EP0738823A2 publication Critical patent/EP0738823A2/fr
Publication of EP0738823A3 publication Critical patent/EP0738823A3/fr
Application granted granted Critical
Publication of EP0738823B1 publication Critical patent/EP0738823B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
    • E21B10/56—Button-type inserts
    • E21B10/567—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts
    • E21B10/573—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts characterised by support details, e.g. the substrate construction or the interface between the substrate and the cutting element
    • E21B10/5735—Interface between the substrate and the cutting element

Definitions

  • the invention relates to elements faced with superhard material, and particularly to preform elements comprising a facing table of superhard material having a front face, a peripheral surface, and a rear surface bonded to a substrate of material which is less hard than the superhard material.
  • Preform elements of this kind are often used as cutting elements on rotary drag-type drill bits, and the present invention will be particularly described in relation to such use.
  • the invention is not restricted to cutting elements for this particular use, and may relate to preform elements for other purposes.
  • elements faced with superhard material, of the kind referred to may also be employed in workpiece-shaping tools, high pressure nozzles, wire-drawing dies, bearings and other parts subject to sliding wear, as well as elements subject to percussive loads as may be the case in tappets, cams, cam followers, and similar devices in which a surface of high wear resistance is required.
  • Preform elements used as cutting elements in rotary drill bits usually have a facing table of polycrystalline diamond, although other superhard materials are available, such as cubic boron nitride.
  • the substrate of less hard material is often formed from cemented tungsten carbide, and the facing table and substrate are bonded together during formation of the element in a high pressure, high temperature forming press. This forming process is well known and will not be described in detail.
  • Each preform cutting element may be mounted on a carrier in the form of a generally cylindrical stud or post received in a socket in the body of the drill bit.
  • the carrier is often formed from cemented tungsten carbide, the surface of the substrate being brazed to a surface on the carrier, for example by a process known as "LS bonding".
  • the substrate itself may be of sufficient thickness as to provide, in effect, a cylindrical stud which is sufficiently long to be directly received in a socket in the bit body, without being brazed to a carrier.
  • the bit body itself may be machined from metal, usually steel, or may be moulded using a powder metallurgy process.
  • Such cutting elements are subjected to extremes of temperature during formation and mounting on the bit body, and are also subjected to high temperatures and heavy loads when the drill is in use down a borehole. It is found that as a result of such conditions spalling and delamination of the superhard facing table can occur, that is to say the separation and loss of the diamond or other superhard material over the cutting surface of the table.
  • U.S. Patent Specification No. 5120327 where the rear surface of the facing table is integrally formed with a plurality of identical spaced apart parallel ridges of constant depth.
  • the facing table also includes a peripheral ring of greater thickness, the extremities of the parallel ridges intersecting the surrounding ring.
  • U.S. Specification No. 4784023 illustrates a similar arrangement but without the peripheral ring.
  • a preform element including a facing table of superhard material having a front face, a peripheral surface, and a rear surface bonded to a substrate which is less hard than the superhard material, the rear surface of the facing table being integrally formed with a plurality of ribs which project into the substrate, at least major portions of said ribs extending across the rear surface of the facing table in directions which are generally radial with respect to a point adjacent or outside the peripheral surface of the facing table.
  • the ribs may comprise two or more sets of ribs, the ribs of one set being generally radial with respect to a point adjacent or outside the peripheral surface, and the ribs of the other set or sets being generally radial with respect to a different point or points. Said different point or points are also preferably adjacent or outside the peripheral surface.
  • the rear surface of the facing table may also be formed with one or more other ribs, or protuberances, which are not generally radial with respect to said point or points.
  • each rib is substantially continuous as it extends across the rear surface of the facing table.
  • the ends of at least some of said ribs extend to locations at or adjacent the peripheral surface of the facing table.
  • the ends of said ribs which are further from said point may extend to locations at or adjacent the peripheral surface of the facing table, the opposite ends of the ribs, nearer said point, being spaced inwardly of the peripheral edge of the facing table.
  • the ends of at least some of the ribs which are nearer said point may be located on a circular arc centred on said point.
  • the ribs may comprise two or more sets of ribs, the ends of the ribs which are nearer said point, in each set, being located on circular arcs of different radii centred on said point.
  • the ribs of one set may lie interjacent ribs of another set.
  • the ribs may be inclined at substantially equal angles to one another.
  • the ends of the ribs which are located at or adjacent the peripheral surface of the facing table may be spaced apart at substantially equal distances around part of said peripheral surface.
  • parts of the outer peripheral surface of the facing table may be formed with a peripheral wall portion which projects rearwardly from the periphery of the facing table.
  • the ends of at least some of the aforesaid ribs which are further from said point may intersect the peripheral wall portion.
  • the depth of each such rib, where it intersects the peripheral wall portion is preferably greater than the depth of the wall portion.
  • At least some of the ribs may vary in depth, for example linearly, along the length thereof. At least some of the ribs may increase in depth as they extend away from said point adjacent or outside the peripheral surface of the facing table.
  • Each rib may taper in width, preferably outwardly, as it extends away from said point.
  • Each rib may be generally triangular in cross-section.
  • the apex of each rib, remote from the rear surface of the facing table, may be radiused as viewed in cross-section.
  • One rib which extends to the peripheral surface of the facing table is preferably of different depth, for example of greater depth, than the other ribs which extend to the peripheral surface of the facing table.
  • a centre rib of a set of ribs Preferably such rib is a centre rib of a set of ribs. The different depth of the centre rib may thus provide a visual indication of the location of the array of ribs in order to facilitate orientation of the preform element in use.
  • Some or all of said ribs may include portions of the length thereof which deviate from the radial direction with respect to said point adjacent or outside the peripheral surface of the facing table.
  • an end portion of each rib further from said point may deviate from said radial direction in a manner to approach the peripheral surface of the facing table in a direction normal thereto. Said end portions may deviate in smooth curvilinear fashion.
  • a buffer or transition layer between the superhard material and the less hard material may be provided.
  • transition layers normally comprise material having one or more properties, such as coefficient of thermal expansion and/or elastic modulus, which is intermediate the corresponding properties of the superhard and less hard materials.
  • the buffer or transmission layer may, for the purposes of the present invention, be regarded either as a part of the facing table or as a part of the substrate.
  • the ribs arranged according to the present invention may be provided at the interface between the superhard material and the buffer/transition layer, or between the buffer/transition layer and the less hard material, or at both said interfaces.
  • the invention also includes within its scope arrangements where one of said interfaces is configured with ribs in accordance with the present invention and the other interface is configured, so as to be non-planar, in a different manner.
  • any of the facing table, the substrate, and the buffer/transition layer may comprise a plurality of different layers or portions bonded together and do not necessarily comprise a unitary body of material.
  • Figures 1 and 2 show a typical full bore drag-bit of a kind to which cutting elements of the present invention are applicable.
  • the bit body 10 is machined from steel and has a shank formed with an externally threaded tapered pin 11 at one end for connection to the drill string.
  • the operative end face 12 of the bit body is formed with a number of blades 13 radiating from the central area of the bit, and the blades carry cutter assemblies 14 spaced apart along the length thereof.
  • the bit has a gauge section including kickers 16 which contact the walls of the borehole to stabilise the bit in the borehole.
  • a central passage (not shown) in the bit and shank delivers drilling fluid through nozzles 17 in the end face 12 in known manner.
  • Each cutter assembly 14 comprises a preform cutting element 18 mounted on a carrier 19 in the form of a post which is located in a socket in the bit body.
  • Each preform cutting element is in the form of a circular tablet comprising a facing table of superhard material, usually polycrystalline diamond, bonded to a substrate which is normally of cemented tungsten carbide. The rear surface of the substrate is bonded, for example by LS bonding, to a suitably orientated surface on the post 19.
  • the cutting element comprises a polycrystalline diamond front facing table 20 bonded to a cemented tungsten carbide substrate 21.
  • the facing table 20 comprises a front flat layer 22 which provides the front cutting face 23 of the facing table, and a peripheral wall 24 is integrally formed with the front layer 22 and extends rearwardly therefrom around the periphery of the cutting element.
  • a plurality of ribs 25, 26 which project rearwardly from the rear surface 27 of the front layer 22 and into the substrate 21.
  • Figure 3 shows the rear surface of the facing table 20 formed with the peripheral wall 24 and the ribs 25, 26. As may be seen from Figure 3, there are provided seven ribs 25, 26 all of which extend across the rear surface of the facing table in directions and which are generally radial with respect to a point 28 located outside the peripheral surface 29 of the facing table.
  • the ends of the ribs 25, 26 which are further from the point 28 extend to the peripheral edge 29 of the facing table and intersect the peripheral wall 24.
  • the ends of the ribs are spaced apart at equal distances around part of the peripheral surface 29 of the facing table, for example, the distance between the ends of the ribs may subtend an angle of 20° at the centre of the facing table.
  • the ribs 25 lie interjacent the ribs 26.
  • the ends of the ribs 25 which are nearer the point 28 are located on a circular arc 30 centred on the point 28.
  • the radius of the arc 30 is such that the nearer ends of the ribs 25 are spaced inwardly from the peripheral wall 24 of the facing table.
  • the other ribs 26 have their nearer ends located on an arc 31 which is also centred on the point 28, but which is of greater radius than the arc 30 so that the ribs 26 are shorter than the ribs 25, their ends being spaced a greater distance from the point 28.
  • the ribs 25 and 26 taper outwardly slightly as they extend away from the point 28.
  • the ribs 25 and 26 also increase in depth as they extend away from the point 28 towards the opposite peripheral surface 29 of the facing table.
  • the ribs increase linearly in depth so that their lower edges are straight.
  • the lower edges of the ribs may be curved, preferably concavely curved.
  • the lower edges of the ribs may follow a part circular or parabolic curve.
  • the ribs are generally triangular as viewed in cross-section, the apex of each rib, remote from the rear surface of the facing table, being radiused.
  • the ribs may also be of any other suitable cross-sectional shape, e. g. they may be generally rectangular or U-shaped in cross-section.
  • the maximum depth of the ribs 25 or 26 at the peripheral surface 29 of the facing table may be the same. Since the ribs are of different lengths, this means that the longitudinal shapes of the rib are different. Preferably, however, one of the ribs, and preferably the central rib 25, has a depth at the peripheral surface 29 which is greater (or less) than the depth of the other ribs. This therefore provides a visual indication of where the centre of the array of ribs is, and this can assist in orientating the cutting element on its carrier or when mounting it on the drill bit. It is desirable that the portion of the periphery of the cutting element where the ribs intersect the peripheral surface 29 is used as the cutting edge of the cutting element in use.
  • a substrate 21 is first preformed by machining or moulding to the shape shown in Figure 7.
  • the substrate 21 comprises basically a circular disc of cemented tungsten carbide formed around its periphery with an annular groove 32 of complementary shape to the peripheral wall 24, and across its upper surface with grooves 33 complementary in shape and arrangement to the ribs 25, 26 on the rear surface of the facing table.
  • the preformed substrate 21 is then placed in a mould and, in known manner, diamond particles are packed in a layer above the substrate so as to fill the annular groove 32 and the grooves 33 and to form a flat top layer above the substrate.
  • the substrate and diamond layer is then subjected to extremely high pressure and temperature in a press so that diamond-to-diamond bonding occurs between the diamond particles to form a facing layer of polycrystalline diamond which is bonded to the substrate 21.
  • the preform substrate 21 thus acts as a mould to form the peripheral wall 24 and ribs 25, 26 on the rear surface of the diamond layer.
  • some or all of the ribs 25, 26 may include portions which deviate from the radial direction with respect to the point 28.
  • an end portion of each rib at the end further from the point 28 may curve smoothly outwardly away from the radial direction so as to approach the peripheral surface 29 of the facing table in a direction normal thereto.
  • some ribs may be radial with respect to one point and other ribs may be radial with respect to another point.
  • the longer ribs 25 may extend radially with respect to a point which is spaced from the point 28.
  • the other point may be further from the peripheral surface 29 of the facing table than the point 28.
  • the two or more points with respect to which the ribs are radial may lie on a common diametral line. Alternatively they may lie on different diametral lines, in which case the two or more sets of ribs may intersect as they extend across the surface of the facing table.
  • the ribs are in two or more sets which are radial with respect to different points, it is only necessary for the purposes of the invention for at least one of said points to be adjacent or outside the peripheral surface of the facing table.
  • the other point or points may also be adjacent or outside the peripheral surface of the facing table, as previously mentioned the invention includes arrangement where said other point or points are located elsewhere, for example within the facing table.
  • the array of ribs, or each array of ribs is substantially symmetrical with respect to the diametral line on which the point from which they radiate lies., as in the arrangement of Figure 3.
  • the ribs may be asymmetrical with respect to that diametral line.
  • the number and/or spacing of the ribs may be different on each side of the diametral line.
  • the facing table may also be formed with one or more other ribs, or protuberances, which are not arranged according to the present invention.
  • a buffer or transition layer may be provided between the superhard material of the facing table 20 and the less hard material of the substrate 21.
  • the buffer/transition layer may be regarded as forming part of the substrate.
  • the ribs may be formed at the interface between the buffer/transition layer and the substrate 21, in which case the buffer/transition layer may be regarded as forming part of the facing table.
  • the interface between the buffer/transition layer which is not formed with ribs in accordance with the present invention may be otherwise configured to provide a non-planar interface.
  • both interfaces may be formed with ribs arranged in accordance with the present invention.

Claims (28)

  1. Elément d'ébauche englobant une table de dressage (20) en matériau superdur comportant une face avant (23), une surface périphérique (29) et une surface arrière (27) reliée à un substrat (21) moins dur que le matériau superdur, la surface arrière de la table de dressage comportant plusieurs nervures solidaires (25, 26) débordant dans le substrat, caractérisé en ce qu'au moins les majeures parties desdites nervures (25, 26) s'étendent à travers la surface arrière (27) de la table de dressage (20) dans des directions généralement radiales par rapport à au moins un point (28) adjacent ou externe à la surface périphérique (29) de la table de dressage.
  2. Elément d'ébauche selon la revendication 1, dans lequel les nervures comprennent deux ou plusieurs groupes de nervures, les nervures d'un groupe étant en général radiales par rapport un point adjacent ou externe à la surface périphérique, les nervures de l'autre groupe ou des autres groupes étant généralement radiales par rapport à un point ou des points différents.
  3. Elément d'ébauche selon la revendication 2, dans lequel ledit point différent ou lesdits points différents sont aussi adjacents ou externes à la surface périphérique.
  4. Elément d'ébauche selon l'une quelconque des revendications 1 à 3, dans lequel la surface arrière de la table de dressage comporte aussi une ou plusieurs nervures, ou protubérances, non généralement radiales par rapport audit point ou auxdits points.
  5. Elément d'ébauche selon l'une quelconque des revendications 1 à 4, dans lequel chaque nervure (25, 26) est pratiquement continue lors de son extension à travers la surface arrière de la table de dressage.
  6. Elément d'ébauche selon l'une quelconque des revendications 1 à 5, dans lequel les extrémités d'au moins certaines desdites nervures (25, 26) s'étendent vers des emplacements situés au niveau de la surface périphérique (29) de la table de dressage ou en un point adjacent à celle-ci.
  7. Elément d'ébauche selon l'une quelconque des revendications 1 à 6, dans lequel les extrémités d'au moins certaines desdites nervures (25, 26) plus éloignées dudit point (28) s'étendent vers des emplacements situés au niveau de la surface périphérique (29) de la table de dressage ou en un point adjacent à celle-ci, les extrémités opposées des nervures plus proches dudit point étant espacées vers l'intérieur du bord périphérique de la table de dressage.
  8. Elément d'ébauche selon l'une quelconque des revendications 1 à 7, dans lequel les extrémités d'au moins certaines desdites nervures (25, 26) plus proches dudit point (28) sont agencées sur un arc circulaire (30) centré sur ledit point.
  9. Elément d'ébauche selon la revendication 8, dans lequel les nervures (25, 26) comprennent deux ou plusieurs groupes de nervures, les extrémités des nervures plus proches dudit point (28), dans chaque groupe, étant agencées sur des arcs circulaires (30, 31) ayant des rayons différents centrés sur ledit point.
  10. Elément d'ébauche selon l'une quelconque des revendications 1 à 9, comportant deux ou plusieurs groupes de nervures, les nervures d'un groupe (25) étant agencées entre les rainures de l'autre groupe (26).
  11. Elément d'ébauche selon l'une quelconque des revendications 1 à 10, dans lequel les nervures (25, 26) sont inclinées à des angles pratiquement égaux.
  12. Elément d'ébauche selon l'une quelconque des revendications 1 à 10, dans lequel les extrémités desdites nervures plus éloignées dudit point s'étendent vers des emplacements situés au niveau de la surface périphérique de la table de dressage, ou en un point adjacent à celle-ci, et sont espacés de distances pratiquement égales autour d'une partie de ladite surface périphérique.
  13. Elément d'ébauche selon l'une quelconque des revendications 1 à 12, dans lequel des parties de la surface périphérique externe de la table de dressage (20) comportent une partie de paroi périphérique (24) débordant vers l'arrière à partir de la périphérie de la table de dressage.
  14. Elément d'ébauche selon la revendication 13, dans lequel les extrémités d'au moins certaines des nervures ci-dessus (25, 26), plus éloignées dudit point (28), coupent la partie de paroi périphérique (24).
  15. Elément d'ébauche selon la revendication 14, dans lequel la profondeur de chacune de ces nervures (25, 26), au niveau de son intersection avec la partie de paroi périphérique (24), est supérieure à la profondeur de la partie de paroi.
  16. Elément d'ébauche selon l'une quelconque des revendications 1 à 15, dans lequel au moins certaines de nervures (25, 26) ont une profondeur variable le long de la longueur correspondante.
  17. Elément d'ébauche selon l'une quelconque des revendications 1 à 16, dans lequel au moins certaines des nervures ont une profondeur accrue lors de leur extension à l'écart dudit point (28) adjacent ou externe à la surface périphérique de la table de dressage.
  18. Elément d'ébauche selon l'une quelconque des revendications 1 à 17, dans lequel chaque nervure a une largeur effilée lors de son extension à l'écart dudit point (28).
  19. Elément d'ébauche selon l'une quelconque des revendications 1 à 18, dans lequel chaque nervure (25, 26) a une section transversale généralement triangulaire.
  20. Elément d'ébauche selon l'une quelconque des revendications 1 à 18, dans lequel le sommet de chaque nervure (25, 26) éloigné de la surface arrière de la table de dressage (20) est arrondi, vu en section transversale.
  21. Elément d'ébauche selon l'une quelconque des revendications 1 à 20, dans lequel une nervure s'étendant vers la surface périphérique de la table de dressage a une profondeur différente de celle des autres nervures s'étendant vers la surface périphérique de la table de dressage.
  22. Elément d'ébauche selon la revendication 21, dans lequel la nervure de profondeur différente est une nervure centrale d'un groupe de nervures, de sorte à fournir une indication visuelle de l'emplacement de l'agencement de nervures, pour faciliter l'orientation de l'élément d'ébauche en service.
  23. Elément d'ébauche selon l'une quelconque des revendications 1 à 22, dans lequel certaines ou l'ensemble desdites nervures englobent des parties de la longueur correspondante déviant de la direction radiale par rapport audit point adjacent ou externe à la surface périphérique de la table de dressage.
  24. Elément d'ébauche selon la revendication 23, dans lequel une partie d'extrémité de chaque nervure plus éloignée dudit point est déviée de ladite direction radiale de sorte à se rapprocher de la surface périphérique de la table de dressage dans une direction perpendiculaire à celle-ci.
  25. Elément d'ébauche selon l'une quelconque des revendications 1 à 24, dans lequel une couche tampon ou de transition est agencée entre le matériau superdur et le matériau moins dur.
  26. Elément d'ébauche selon la revendication 25, dans lequel la couche de transition est composée de matériau présentant une ou plusieurs propriétés intermédiaires par rapport aux propriétés correspondantes des matériaux superdur et moins dur.
  27. Elément d'ébauche selon les revendications 25 ou 26, dans lequel les nervures sont agencées au niveau de l'interface entre le matériau superdur et la couche tampon/de transition, ou entre la couche tampon/de transition et le matériau moins dur, ou au niveau des deux dites interfaces.
  28. Elément d'ébauche selon l'une quelconque des revendications 1 à 27, dans lequel un quelconque des éléments, la table de dressage, le substrat et la couche tampon/de transition comprend plusieurs couches ou parties différentes reliées les unes aux autres.
EP96302709A 1995-04-22 1996-04-18 Elément de coupe avec une surface en matériaux extra-dur Expired - Lifetime EP0738823B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9508226.9A GB9508226D0 (en) 1995-04-22 1995-04-22 Improvements in or relating to elements faced with superhard material
GB9508226 1995-04-22

Publications (3)

Publication Number Publication Date
EP0738823A2 EP0738823A2 (fr) 1996-10-23
EP0738823A3 EP0738823A3 (fr) 1997-11-05
EP0738823B1 true EP0738823B1 (fr) 2002-07-17

Family

ID=10773377

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96302709A Expired - Lifetime EP0738823B1 (fr) 1995-04-22 1996-04-18 Elément de coupe avec une surface en matériaux extra-dur

Country Status (4)

Country Link
EP (1) EP0738823B1 (fr)
DE (1) DE69622311T2 (fr)
GB (2) GB9508226D0 (fr)
ZA (1) ZA963120B (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6571891B1 (en) * 1996-04-17 2003-06-03 Baker Hughes Incorporated Web cutter
US6082474A (en) * 1997-07-26 2000-07-04 Camco International Limited Elements faced with superhard material
DE69820349T2 (de) * 1997-07-26 2004-10-28 Camco International (Uk) Ltd., Stonehouse Verbesserungen an Schneidelementen mit einer Oberfläche aus superhartem Werkstoff
US6202771B1 (en) * 1997-09-23 2001-03-20 Baker Hughes Incorporated Cutting element with controlled superabrasive contact area, drill bits so equipped
GB9809690D0 (en) 1998-05-08 1998-07-01 Camco Int Uk Ltd Improvements in elements faced with superhard material
US6488106B1 (en) 2001-02-05 2002-12-03 Varel International, Inc. Superabrasive cutting element
US9138872B2 (en) 2013-03-13 2015-09-22 Diamond Innovations, Inc. Polycrystalline diamond drill blanks with improved carbide interface geometries

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4784023A (en) * 1985-12-05 1988-11-15 Diamant Boart-Stratabit (Usa) Inc. Cutting element having composite formed of cemented carbide substrate and diamond layer and method of making same
US5120327A (en) * 1991-03-05 1992-06-09 Diamant-Boart Stratabit (Usa) Inc. Cutting composite formed of cemented carbide substrate and diamond layer
GB2273306B (en) * 1992-12-10 1996-12-18 Camco Drilling Group Ltd Improvements in or relating to cutting elements for rotary drill bits
US5351772A (en) * 1993-02-10 1994-10-04 Baker Hughes, Incorporated Polycrystalline diamond cutting element
GB2308142B (en) * 1993-11-10 1998-02-25 Camco Drilling Group Ltd Improvements in or relating to elements faced with superhard material
GB2283772B (en) * 1993-11-10 1997-01-15 Camco Drilling Group Ltd Improvements in or relating to elements faced with superhard material
GB9412247D0 (en) * 1994-06-18 1994-08-10 Camco Drilling Group Ltd Improvements in or relating to elements faced with superhard material

Also Published As

Publication number Publication date
ZA963120B (en) 1996-10-24
DE69622311D1 (de) 2002-08-22
GB2300016A (en) 1996-10-23
DE69622311T2 (de) 2003-02-20
GB9508226D0 (en) 1995-06-07
GB2300016B (en) 1998-12-02
GB9608077D0 (en) 1996-06-19
EP0738823A2 (fr) 1996-10-23
EP0738823A3 (fr) 1997-11-05

Similar Documents

Publication Publication Date Title
EP0688937B1 (fr) Améliorations à ou concernant des éléments couverts d'un matériau superdur
US5788001A (en) Elements faced with superhard material
EP0655549B1 (fr) Améliorations à ou concernant des éléments couverts d'un matériau superdur
US5611649A (en) Elements faced with superhard material
EP0733777B1 (fr) Elément de coupe pour trépan racleur
US5888619A (en) Elements faced with superhard material
US5740874A (en) Cutting elements for rotary drill bits
EP0655548B1 (fr) Améliorations à ou concernant des éléments couverts d'un matériau superdur
US6082474A (en) Elements faced with superhard material
GB2283772A (en) Improvements in or relating to elements faced with superhard material
GB2308144A (en) Improvements relating to elements faced with superhard material
US6077591A (en) Elements faced with superhard material
EP0962621B1 (fr) Eléments préformés pour trépans de forage rotatif
EP0738823B1 (fr) Elément de coupe avec une surface en matériaux extra-dur
EP0893572B1 (fr) Amélioration des éléments de coupe avec une surface en materiaux extra-dur
EP0936012A1 (fr) Eléments couverts de matériau superdur
GB2300437A (en) Cutting elements for rotary drill bits
EP0878602A2 (fr) Elément de coupe avec une surface en matériaux extra-dur
GB2331538A (en) Preform elements faced with a superhard material

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): BE DE FR IE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): BE DE FR IE

17P Request for examination filed

Effective date: 19980420

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

17Q First examination report despatched

Effective date: 20011112

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): BE DE FR IE

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 69622311

Country of ref document: DE

Date of ref document: 20020822

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20030422

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20050408

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IE

Payment date: 20050414

Year of fee payment: 10

Ref country code: DE

Payment date: 20050414

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20050610

Year of fee payment: 10

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060418

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20061101

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20061230

BERE Be: lapsed

Owner name: *CAMCO DRILLING GROUP LTD

Effective date: 20060430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060502