Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS3800891 A
Publication typeGrant
Publication dateApr 2, 1974
Filing dateApr 18, 1968
Priority dateApr 18, 1968
Publication numberUS 3800891 A, US 3800891A, US-A-3800891, US3800891 A, US3800891A
InventorsWhite A, Wisler A
Original AssigneeHughes Tool Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hardfacing compositions and gage hardfacing on rolling cutter rock bits
US 3800891 A
The novel hardfacing compositions are sintered tungsten carbide granules in an alloy steel matrix, the granules consisting of grains of monotungsten carbide cemented together with a number of novel binders - iron, nickel, alloys of the three iron group metals and metallic alloys including at least one iron group metal and at least one metal outside such group. Also disclosed are granules comprising a mixture of monotungsten carbide and ditungsten carbide cemented together with a metallic binder, preferably iron.
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Unite States Patent Primary Examiner-Nile C. Byers, Jr.

White et al. Apr. 2, 1974 IIARDFACING COMPOSITIONS AND GAGE IIARIIFACING ON ROLLING CUTTER [57] ABSTRACT ROCK BITS The novel hardfacing compositions are sintered tungl75] Inventors: Anderson white; Allen E wish", stcn carbide granules in an alloy steel matrix, the granboth of Houston, ules consisting of grains of monotungsten carbide cemented together with a number of novel binders Assigfleel Hughes T00] p y Houston, iron, nickel, alloys of the three iron group metals and Tax? metallic alloys including at least one iron group metal [22] Filed. AP 18, 1968 and at least one metal outside such group. Also disclosed are granules comprising a mixture of mono- W PP 730,671 tungsten carbide and ditungsten carbide cemented to- Related Application Data gether with a metallic binder, preferably iron. 7 [63] continuatiommpart of 515,603, 22, Such hardfacings are particularly useful when welded 9 5 abandoned to the gage surfaces of rolling cutters of rock bits, particularly rolling cone cutters made of alloy steel. In [52] us. CI. 175/374 such applications the g l r p f y of 51 Int. Cl. E216 13/00 rounded and chunky shapes, avoiding the Sharp edges [58] Fi ld f S h 175/374, 375, 409 410 and corners and the slivery shapes which are likely to 175/411; 29 492 132 132 1 22 323 go into solution with the matrix. Part of the matrix 132] 1823 198 473 1 comes from the melted surface of the alloy steel cutter and part preferably comes from a hardfacing welding [56] References Cit d tube containing the granules.

UNITED STATES PATENTS These rolling cutter gage hardfacings may also utilize 2,407,642 9 1946 Ashworth 175 374 x Compositions heretofore known but not Previously 2 0 405 953 Scott y 175/375 used as gage hardfacings, e.g., monotungsten carbide 2,833,520 5/1958 Owen 175/409 X granules with a cobalt binder. Success achieved by the 2,887,302 5/1959 Garner.... 175/374 inventors may be attributable in part to powders of ,68 6/ Payne l 4 l75/375 ferromanganese and ferromolybdenum added with the 11201285 2/1964 Rowleym 175/409 X granules as part of the filler in the welding tube, a 1165322 H1965 29/1827 preferred pre-application composition being about 1.0 3,279,049 10/1966 Ellls 29/473.l X 3,380,861 4/1968 Frehn 29 1827 x percfim manganese percent molybdenum ance essentiallylow carbon steel.


FIGURE 2 ATTORNEY PATENTEUAPR 2 9974 :mLE I 2 Ur FIGURE 5 PRIOR ART FIGURE 6 ANDERSON D. WHITE ALLEN E. WISLER INvENTORs ATTORNEY PATENYEDAPR 2 I974 SHEET 3 8F 3 8 E R U W F FIGURE 7 E R U m F 3 INVENTORS ATTORNEY FIGURE 11 HARDFACHNG COMPOSITIONS AND GAGE HARDFACING N ROLLING CUTTER ROCK BITS The present application is a continuation-in-part of a co-pending application of the same inventors, Ser. No. 515.603, filed Dec. 22, 19b5, now abandoned Apr. 18.

The present invention relates to various cutting tools and abrasion resistant tools, particularly rolling cutter rock bits and more specifically to wear resistant weldments or hardfacings in the gage surfaces of the cutters of such bits. Even more specifically, it deals with such hardfacings of tungsten carbide together with a binder including an iron group metal and a steel alloy matrix.

The typical rolling cutter of a rotary rock bit has the general shape of a bi-frusto conical shell, the interior surface constituting a bearing while the outside contains the cutting structure. The cutter is mounted on a bearing pin extending angularly down and in from the periphery of the bit head towards its center (and the center of the hole) so that the lowermost part of one of the conical surfaces, usually much larger than the other, lies generally horizontally on the bottom and cuts such bottom as weight and torque are applied to the bit. The motion is generally the same as it would be if the cutter were laid on such main conical surface and rolled without restraint, although in some designs the center line of the bearing pin is deliberately offset from the center of the bit to induce a certain amount of skidding and scraping. In addition, some such skidding and scraping is purposely introduced by designing the bit so that the apex or projected apex of the conical surface falls to one side of the bit axis.

This larger conical surface terminates outwardly at a maximum diameter ring (measured from the cutters own axis) commonly referred to as a gage point, at which point it intersects the second and smaller conical surface. The second conical surface extends from the gage point in the opposite direction from the main conical surface, inwardly toward the cutter axis, and terminates at the outer edge of an annular surface which surrounds the open mouth of the cutter. The cutter is designed so that when it is mounted on its bearing pin on a vertically disposed bit the portion of this smaller conical surface lying at the greatest distance from the bit axis will also be vertical and will be spaced from such axis, assuming no wear, the full radius of the desired hole. Since the small cutter surface has as a major chore maintaining the full gage of the borehole, it has come to be known as the gage surface of the cutter. The importance of such gage-maintaining function in an oilwell can scarcely be exaggerated. Since all subsequent operations such as running in casing and cementing it in place depend on having a full gage hole, the customer demands and obtains it in one way or another. lf a bit drills an undersize hole, the following bit must be used to ream the hole to full gage, even if in so doing the second bit becomes useless for further drilling. Needless to say, the bit which drilled the undersize hole will not be reordered if a better one is available.

Thus the gage surface of a rolling cutter used in oilfield drilling is completely unlike many other bits used in drilling rock, and must even be better than the bottom-cutting structure of the same rolling cutter on which it is employed. Wear ofa gage surface cannot be tolerated, whereas it makes little difference if the teeth which cut the inner part of the hole gradually wear away, so long as they continue to penetrate effectively. Similarly, drag bits and other drills used to dig shot holes and the like may wear away even on their gage surfaces, as the diameters of such holes are not critical and can taper downwardly and inwardly without ill effeet.

The prior art relating to rock penetrating bits is thus of little value as guidance in seeking improvements in the gage surfaces of rolling cutters used in drilling full diameter holes except for that segment of the prior art dealing specifically with such gage surfaces of rolling cutters of oilfield bits.

Even when the prior art deals with gage surfaces aimed at maintaining full gage, it is of little value if the bit is not a rolling cutter type, i.e., if it is a drag blade bit or equivalent. A gage surface of a rolling cutter may be thought of as a number of discrete pads, each pad lying on the smaller conical surface of the cutter, the axis of which surface has an axis coincident with the inclined bearing pin axis. Each pad rotates around such pin axis and also moves around the bottom of the hole as the bearing pin rotates about the center of the hole and the cutter rolls on the bottom.

When one considers the motion of any one of these pads relative to the sidewall of the hole, it becomes apparent that such motion is quite complex. Any one hardfacing pad is constantly changing velocity relative to the sidewall, both in magnitude and direction. During most ofa cone revolution the pad is out of contact, but as it contacts the sidewall it passes through a point of maximum relative velocity, i.e., it is shock loaded. Even during such contact the relative velocity is changing, and in addition to the circumferential motions there is a downward motion as the cutters bite deeper into the formation. The result is a constantly changing, high magnitude shearing force on the gage hardfacing, during which it is required to exert a combined abrading and crushing action on the sidewall to keep it cut to a full diameter hole. The action is such as to constantly tend to push or pull the gage material out of the cone. The hardfacing must resist this action, because the gradual loosening and falling out of the hard granules, by erosion of the matrix in which they are embedded, tolerable in drag bits and other cutting structures, cannot be tolerated in the gage hardfacing of an oilfield rolling cutter bit.

The proper design of the gage surface and the cutting structure of the adjacent heel teeth, those outermost teeth which extent to the gage point and cut the bottom immediately adjacent the sidewall of the hole, has long been one of the most difficult problems facing the team of mechanical and metallurgical engineers who design rock bits. The cutter is subject to maximum abrasive contact with the formation being drilled at this outside area of the hole and must there do the maximum amount of rock removal, both because the cutter travels over the maximum diameter at the gage point and because the formation is toughest at the intersection of the bottom and sidewall. In some hard formations which are very abrasive, e.g., sandy limestone and sandy shale, the abrasion on the gage surface wears it away so rapidly that the bit wears under gage and must be pulled long before its cutting structure has been dulled.

To overcome these problems, rock bit metallurgists have been seeking appropriately tough and wear resistant materials since the infancy of rotary drilling. By comparison with metal carbides, the hardest of the hard metal alloys have little wear resistance and have been abandoned in favor of carbides since as early as 1927 or 1928. In particular, tungsten carbide has been used for entire parts and as a coating or hardfacing on many earth drilling tools since about that early year.

Broadly speaking, however, there are two basically different types of tungsten carbide, the cast carbide and the sintered or cemented carbide. Cast tungsten carbide is essentially a eutectic of the monotungsten carbide and the ditungsten carbide, WC and W C, while sintered carbide in the past has been essentially pure WC. ln the cast carbide, there is no additional material holding the grains of a granule together, while in sintered tungsten carbide granules each grain is surrounded by an iron group binder, such binder being a continuous phase which binds or cements the grains together. The usual binder has been cobalt, and it is usually added to form 3 to percent of the total weight of the granule.

The cast carbide is actually the harder and more abrasive of the two, and when it can stand the impacts to which it is subject without undue crumbling it will protect against wear better than the sintered material. On the other hand, sintered carbide is tougher than cast carbide, and will withstand repeated impacts with less breakage and crumbling. For this reason sintered tungsten carbide is preferred for such shapes as inlays of massive carbide for drag bit teeth and inserts or compacts forming the cutting structure of button bits.

With respect to gage hardfacing of rolling cutters, however, insofar as known cast tungsten carbide has been used exclusively from the beginning of the industry to the advent of the present invention. To a large extent this choice of materials has been deliberate, because the cast carbide does have superior wear resistance and probably would always be chosen if it would hold up in service. Since there are rock formations and drilling conditions which so load and jar the gage surface that cast carbide hardfacings tend to crumble prematurely, repeated attempts have been made over the years to use sintered carbides, sometimes as inlays in the gage surface and sometimes as hardfacings welded into recesses in the gage. Until the present time such attempts have been unpromising or outright failures, the carbide material crumbling, cracking, tearing out or otherwise failing well before a comparable cast carbide gage hardfacing.

Such failures are eliminated in the gage hardfacing of the present invention, although it is not completely clear why the present invention provides excellent sintered hardfacings and previous attempts did not. One explanation may lie in the nature of the matrix, a consideration not mentioned above. As used herein, the term matrix means the material immediately surrounding the carbide granules, material which has been fused and allowed to resolidify during the welding process; it includes the portion of the tool surface which is melted during welding as well as any material added with the carbide granules, and is distinguished here from the cobalt or other binder surrounding the grains of individual granules and knitting them together in a cohesive entity. To some extent, tungsten carbide is soluble in various steel matrices, and it is believed to be undesirable if too large an amount enters the matrix and shrinks the size of the carbide granules of the cooled and finished hardfacing. The carbide entering the matrix may increase the hardness of the matrix to such an extent that it becomes brittle and easily fractured in service. The present invention may owe its success at least in part to the materials added with the carbide to control the composition of the matrix, as these may well decrease the solubility of the carbide in such matrix.

The present invention, in one of its broadest and simplest aspects, is that of substituting sintered tungsten carbide granules for the cast fragments of tungsten carbide known in the prior art, other constituents and procedures being essentially the same. The invention also involves varying the type of metallic binder used to knit the tungsten carbide grains into a tough, abrasive granule, employing not only the usual cobalt but alternative binders including either of the other iron group metals (iron and nickel), the various binary and ternary alloys of the iron group metals, and metallic binders in which one or more iron group metals form the principal part of the binder and various other metals form the balance. The generally useful range of the binder fraction of the granules is 3 to 15 percent by weight, about 6 percent being the preferred fraction. The granules are preferably of rounded and roughly spherical shapes, avoiding sharp edges and slivers which can easily go into solution in the welding matrix. The size of the granules is not critical, a range of 0.009 inch to 0.093 inch largest cross sectional dimensions being typical of the present invention. The compositions using tungsten, carbide with binders other than cobalt are believed to be novel in applications on all cutting tools and surfaces requiring abrasion resistance, and are so claimed at the end of the present specification.

Another important aspect of the present invention is the nature of the matrix which secures the sintered carbide granules to the gage surface of the cutter. This matrix is a tough and fairly hard alloy steel, the hardness being in the range of about 44 to about 63 Rockwell C and preferably within 58 to 62 of such range, as applicants have discovered that matrices such as ordinary steels, brazing materials and very hard steels are either too weak or too brittle to withstand the constant shear stress experienced in service. The alloy steel of the matrix is derived partly from the alloy steel cutter, typically a nickel-molybdenum steel, and partly from the welding rod or tube, or sometimes almost entirely from the portion of the cutter surface melted in the welding process, the tube supplying only low carbon steel. Various welding methods may be used, e.g., atomic hydrogen or oxy-acetyle'ne, and the hardfacing granules may be applied in advance of welding, as by sticking them to the gage surface with an adhesive like sodium silicate, or, preferably, are applied from a steel welding tube with the granules constituting a filler for the tube. The raw material mix for such tubes is preferably 30 or 40 weight percent matrix, the balance being the cemented carbide granules.

The powders added with the granules are also of some significance, as to some extent they both control the final hardness of the matrix and limit the amount of tungsten carbide which goes into solution. A preferred technique is to add powders of ferrom'olybdenum and ferromanganese to give a pre-application matrix composition, including the typically low carbon steel wall of the tube, of about LO percent manganese and 0.25 percent molybdenum, balance essentially low carbon steel. Lower percentages of manganese and molybdenum down to zero of each are satisfactory, although not quite as good, while percentages as high as the 2.0 percent mangangese and 0.5 percent molybdenum used with the prior art cast carbide result in a hardfacing which is generally too hard and brittle (hardness about 65 Rockwell C). I j

A final important aspect of the invention is the discovery by the undersigned that a generous fraction of the tungsten carbide, and perhaps all of it, may be ditungsten carbide W C, despite the fact that the prior art teaches that only the monocarbide, WC, can be sintered and welded. The best results obtained by applicants with WC W C mixtures were with the use of an iron binder, although other binders also appear feasible. This aspect of the invention is believed to possess novelty and utility in all types of hardfacings, whether on cutting tools such as rock bits and other cutting tools, or on tool joints and other tools requiring abrasion resistance, and is so claimed at the end hereof.

Several drawing figures are appended to the present specification as a part of the complete application for patent, and in such drawing:

FIG. 1 is a side view of a new 3-cone rock bit using a preferred gage hardfacing of the present invention, the bit being shown suspended from the lowest member of a drilling string at the bottom of a vertical borehole and with the top of the bit slightly tilted away from the observer,

FIG. 2 is a fragmentary view of the gage surface of one of the cutters of the FIG. 1 bit, this view showing the gage surface polished and etched to make the details of the hardfacing visible,

FIG. 3 is a cross section through the structure of FIG. 2, as indicated by the cutting plane and arrows labeled 3-3,

FIG. 4 portrays the same structure as FIG. 3 before the hardfacing was added,

FIG. 5 is a perspective view of a worn bit which was identical to that of FIG. I as manufactured with the gage hardfacing of the present invention and was then used in rock drilling until its bottom cutting structure was completely dulled (but its gage remained full diameter and virtually intact),

FIG. 6 depicts another bit identical as manufactured with the bit of FIG. 1 except that its gage was hardfaced with the cast tungsten carbide of the prior art, the bit thereafter having been run for about the same footage in generally the same type formation as the FIG. 5 bit until it was no longer serviceable, this bit having some bottom cutting structure remaining but having a gage that is so rounded and undersized that it can no longer be used,

FIGS. 7 and 8 are perspective fragmentary views showing alternate gage hardfacings and heel teeth,

FIGS. 9 and 10 are, repsectively, cross sections of the FIGS. 7 and 8 hardfacings as shown by the correspondingly numbered arrows,

FIG. 11 is another fragmentary perspective view of another alternate gage hardfacing and heel tooth arrangement, and

FIG. 12 is a section of FIG. 11.

FIG. 1 shows a typical 3-cone rolling cutter rock bit 1, the particular bit being a 7"/a 7 inch Tricone sealed jet bit of Hughes Tool Company manufacture. The bit is shown dependent from a drill collar 2 into which it is threaded by the usual tapered shank (concealed) upstanding from bit body 3. There are three bit legs 4 equally spaced around the circumference of the body and extending downwardly therefrom, and from each leg 4 a bearing pin not visible in the figure extends downwardly and inwardly toward the axis of the bit. Between adjacent bit legs there is a nozzle boss 6 in which ajet nozzle 7 is secured, and other visible details include a vented compensator cap 8 and a plugged passageway 9 used in loading the bit with lubricant. The bottom and sidewall of the formation in which the hole is being drilled are respectively designated B and S.

On each bearing pin there is journaled an alloy steel rolling cone cutter 11, the particular cutters being made with rnill ed steel teethjlhaving elemental crests 13 and heel teeth 14 webbed together in pairs by webs 15 joining the backs of such heel teeth. It is these backs andwebs 15, interrupted by relief slots 16, that constitute the gage surface of the cutter.

Such gage surface is shown in fragmentary and somewhat enlarged form in FIGS. 2, 3 and 4, from which it will be noted that in the webs 15 there are a number of hardfacing grooves 17 and 18 separated by circumferential ribs 19. Each groove has a bottom 21 and at least one sidewall 22, the groove 18 adjacent gage point 23 having no rib at the gage point. It will be apparent from a comparison of FIG. 3 with FIG. 4, the latter of which shows grooves 17 prior to adding the hardfacing, that the groove contours are altered and rounded when hardfacing 20 is welded into the grooves. Part of the alloy steel cutter metal is fused and combines with the added matrix metal to form a network of matrix metal 24 surrounding granules 25 of the sintered tungsten carbide.

The pattern for the above described hardfacing is substantially that set forth in the patent to L. L. Payne, US. Pat. No. 2,939,684, issued June 7, I960, the present invention having improved on the teachings of Payne only with respect to the use of sintered tungsten carbide, including the use of a number of different binders, and, possibly, an improved matrix for the hardfacing.

The differences between the hardfacing patterns of the FIGS. 14 embodiment and those of FIGS. 7-12 lie entirely in the manner of joining heel teeth 14. Whereas in FIGS. 1-4 the heel teeth are connected by webs 15 running from one crest 13 to the next and relief slots 16 are provided between every other tooth and its neighbor, in the FIGS. 7 and 9 embodiment a single rib 27 projects outwardly from the back of each heel tooth 14 approximately parallel to crest 13 and the balance of the back of the tooth is grooved to receive hardfacing 28. There is no webbing between adjacent teeth, but on the other hand the facing flanks 30 and 31 of adjacent teeth are separated by a gap 32 and a small pad of hardfacing 29 is welded in a groove below this gap, the small pads being separated from the larger pads by relief slots 33. Each hardfacing pad of each type comprises a matrix 24 surrounding spaced granules 25 of sintered tungsten carbide.

The FIGS. 8 and 10 embodiment utilizes a web of alloy steel 36 milled on the back of each heel tooth 14, such web extending in both directions to give the tooth the shape of a A single rib 37 projects outwardly from the leading edge of the cross bar of the T, leaving a rectangular groove 38 which is then filled with a hardfacing pad 39. Between adjacent pads 39, a large relief slot 40 is provided. As in all embodiments, the hardfacing consists of sintered tungsten carbide granules 25 dispersed in a metallic matrix 24.

The hardfacing pattern of FIGS. 11 and 12 is somewhat of a hybrid, combining features of several other patterns. Each heel tooth 14 is provided with a web 43 to give the resulting tooth crest a T configuration, the backs of adjacent teeth being separated by large slots 46. Such backs are first machined to provide alternating circumferential grooves 44 and ribs 45, and secondly are machined with transverse slots 47 extending all the way from the top of wed 43 to the lower edge of the lowermost rib 45. All of these grooves and slots are filled with hardfacing 50, the result being that there are no discrete pads. There are no relief slots between adjacent teeth, the band of hardfacing in the groove 44 closest to radial surface 26 extending around the cutter as a closed annulus.

The worn bits of FIGS. and 6 will now be described in connection with the manner in which they were hardfaced and the field reports describing how they were used in drilling hole. As previously mentioned, both of these bits were virtually identical as manufactured with themselves and with the bit illustrated in FIGS. 14, the only difference being that the FIG. 5 bit was made with the sintered tungsten carbide of the invention while the FIG. 6 bit was made with the cast tungsten carbide of the prior art.

The cemented tungsten carbide granules utilized in the present application may be made in various ways, one preferred method being disclosed by J. R. Whanger in his co-pending application Ser. No. 708,849, filed Jan. 25, 1968, now abandoned and consisting essentially of blending micron size flours of tungsten monocarbide and cobalt or other iron group binder together with wax and a hexane or Chlorgthane NU (1 1, ltrichloroethane) vehicle, pressing into pellets, disintegrating the green pellets through a screen to the desired size, heating and vacuuming to remove wax and vehicle, and sintering the granules in bulk in intimate contact with each other. The resulting loosely bonded granules separate easily along their original boundaries and have rounded, chunky shapes which may be advantageous, especially in that such material lacks sharp, splintery granules which are more likely to be dissolved in the matrix than the chunkier ones.

However, a second preferred method of making the sintered tungsten carbide granules utilized in the present invention differs from the Whanger process described above in that a large block of green material is compacted at high pressure and is then sintered, the result being that in the product emerging from the sintering furnace all particles have lost their original shapes. The block is crushed at high pressure to break it into particles which break from the block along new cleavage surfaces, and these particles are recrushed and screened to obtain the desired range of granule sizes. It is preferred that the granules be ball milled to round off sharp edges and corners, and to eliminate splintery particles of small cross section which could easily go into solution with the matrix.

COMPLETE EXAMPLE The cutters of the FIGS. 1 and 5 bits were hardfaced by the tube method using an oxy-acetylene torch. The granules were of the second type described above, had a binder of 6 percent by weight cobalt, and ranged in size from 0.035 inch to 0.046 inch (passing through No. 14 screen and retained on No. 16 screen, both Tyler Sieve Series). The tube wall was of low carbon steel (0.l5%C maximum, by weight), and sufficient powders of ferromolybdenum and ferromanganese were added with the tungsten carbide granules filling the tube so that the pre-application composition of the matrix was approximately 1.0 weight percent manganese, 0.25 percent molybdenum, balance low carbon steel. The raw material ratio was about 60 weight percent cemented WC, 40 weight percent matrix. This particular matrix melts at about 2,700F. (The matrix also included about 1 weight percent silico-managnese added as a flux, but this material does not go into solution when the matrix is melted except in trace amounts. This material is requied only for oxy-acetylene welding, and may be replaced by other well known fluxes.)

After the hardfacing has cooled, it is ground flat as shown, and the cutters were carburized and heat treated to the desired hardness. The final hardness of the matrix, measured between adjacent tungsten carbide granules, is about 63 Rockwell C.

TwEtRteTs'arma ab r arias "silk-Sikh in FIGTFWiE manufactured in the same manner except that cast tungsten carbide granules of slightly smaller size (0.014

inch to 0.035 inch) were used, and the powders added I with the granules to form the filler of the tube were so proportioned as to give an overall matrix composition of 2.0 weight percent manganese, 0.5 weight percent molybdenum, balance low carbon steel. The weight ratio of tungsten carbide to matrix was about 60 to 40. The matrix melted at 2,700F, and had a final hardness, after carburizing and heat treating, of about 58-62 .RQckwell...Q.

TESTING The 7% inch bits of FIGS. 5 and 6 were run at 74 revolutions per minute under a, weight of 30 to 55,000 pounds in the Blinebry Field of Lea County, N. M., through a section known for being extremely hard on gage wear. The bit of the invention, using a gage hardfacing of sintered tungsten carbide, drilled 31 1 feet of limestone, anhydrite and chert in 20 hours. At that time it was pulled from the hole and had the appearance shown in FIG. 5. Gage wear was measured by a ring gage, a steel ring having a 7 /3 inch inside diameter. The gage was held tight on the gae surfaces 20 of two cutters, but it could not he slipped over the third. It was estimated that the bit was l/64 inch over gauge, and it was evident that there has been substantially no wear of the hardfacing.

The bit hardfaced with cast tungsten carbide followed the bit of the invention in the hole, and drilled 383 feet of limestone and anhydrite in 20 /2 hours, at which time it appeared as in FIG. 6. Using the same ring gage and measuring technique as for the bit of the invention, the bit was found to be l/4th inch under gage. The extreme gage wear can be seen on FIG. 6 by noting that relief slots 16 have virtually disappeared and that the backs of heel teeth 14 on each side of a slot have actually bridged the slot. In the bit of FIG. 5, on the other hand, slots 16 are still well defined and hardfacing pads 20 are still sharp and well separated from each other. (Note that the differences in wear of the bottom cutting teeth 12, despite their complete identity as manufactured, may be accounted for by the lack of chert stringers in the formation cut by the FIG. 6 bit. Chert is one of the most abrasive and well consolidated rocks known.)

Summary Examples Granules of sintered monotungsten carbide having the binder compositions set forth in Table I below were prepared by the Whanger process summarized above, the binder fraction of the granules in each instance being about 6 percent by weight (w/o). Such granules are welded to the gage surfaces of gage cutters by the tube method described in the complete example above, using a pre-application ratio of 60 w/o WC granules to 40 w/o matrix, a low carbon steel tube, and an oxyacetylene torch. The tube filler included sufflcient ferromanganese and ferromolybdenum powders to furnish a matrix having a pre-application composition of approximately 1.0 w/o manganese, 0.25 w/o molybdenum, balance essentially low carbon steel.


176 100 Nickel 177, G47, 226 lOO Iron 178, 230 50 Iron, 50 Nickel 179 4 Iron, 70.3 Nickel, 17

Chromium, 4 Silicon, 3.8 Boron. 0.9 Carbon 180 3 Iron, 83 Nickel, 7

Chromium, 4 Silicon, 3.0 Boron, 0.5 max, Carbon 208 92.7 Nickel, 4.5 Silicon,

2.8 Boron 209 70 Nickel, 30 Copper 648 535 Iron, 46.5 Cobalt 227 96 Iron. 4 Nickel 228 85 Iron, l5 Nickel 229 72 Iron, 28 Nickel 23] 85 Iron, Cobalt 232 l5 Iron, 85 Cobalt 233 50 Nickel, 50 Cobalt 234 75 Nickel. Cobalt 235 25 Nickel. 75 Cobalt rotated and the gage cutter is secured in a ram which presses the gage surface against the rock and forces it to cut annular tracks therein. Many tests of this natrue with the same type of rock and with uniform test conditions have established it as a reliable means for predicting the field performance of newer types of gage hardfacings particularly so because test data on older, field-proven hardfacings have been accumulated over the years and furnish a yardstick to measure the test results on newer hardfacings. The test data consist of l weight of hardfacing abraded away in making the standard number of cuts of the revolving rock, (2) percent length of gage hardfacing remaining after the test, in terms of its original length, and (3) a wear rating" which is a measure of the volume of hardfacing abraded away during the test.

As thus tested and compared with established standards for hardfacings using a 6 percent cobalt binder, all of the binder compositions listed in Table l resulted in gage ha'rdfacings which were at least acceptable, and many ofthem measured up to typical production values or better. The iron group metals iron and nickel appear to be as good as cobalt, the same is true of the various binary alloys of this group, and there is every reason to believe that the ternary iron group alloys would make equally good substitutes.

Substitution of W C In addition to the above discovery of substitute binders, the present inventors have also found that a portion of the tungsten carbide may be of the ditungsten carbide form, W C. Since this form is harder and more abrasive than the WC form, its use could be expected to produce a superior hardfacing, provided it can be secured to the cutter without causing the overall hardfacing to be too brittle. The prior art essentially teaches that a sintered tungsten carbide hardfacing must be 100 percent monotungsten carbide, but the present inventors have discovered that with the proper binder a large fraction of the carbide may be the ditungsten type.

The carbides were formed by mixing powders of tungsten and carbon until an intimate mixture was obtained, and then heating the powders in a hydrogen furnace at about 2,750F. Each powder mixture was then blended with 6 w/o binder w/o tungsten carbide powder) and ball milled with small carbide pellets in hexane for 48 hours. After ball milling, 1% percent soft paraffin was added in more hexane, the mixture was stirred, and excess vehicle removed in a low temperature vacuum oven. The waxed and dried material was then formed into green slugs at a pressure of 4 /2 tons per square inch, and the slugs were broken and hand screened to 5-20 granule size (0.066l inch, +0.033l inch). The granules were then dewaxed in a vacuum oven and sintered in a hydrogen furnace at 2,710-2,730F.

The sintered granules were chemically analyzed, examined under a microscope, and welded by atomic hydrogen torch to gage cutters by the tube method already described, using 40 w/o matrix to 60 w/o granules and a pre-application matrix composition of about 1.0 w/o manganese, 0.25 w/o molybdenum, balance essentially low carbon steel. Such gage cutters were then tested on the laboratory boring mill by the standard test already described. The general nature of the results is indicated in Table II, together with the granule compositions.

TABLE II Test Results Granule Compositions l. 6 w/o cobalt binder, 94 w/o carbide. Carbide was 68.3 W/o WC, 31.7 w/o W C. Mix 062.

2. 6 w/o iron binder, 94 w/o carbide. Carbide was 68.3 w/o WC, 3l.7 W C. Mix 6-53.

3. 6 w/o iron binder, 94 w/o carbide. Carbide was 81.! w/o WC, 18.9 w/o W C. Mix G-55.

4. 6 w/o iron binder, 94 w/o carbide. Carbide was 89.9 w/o WC, lO.l w/o W Cv Mix 6-56.

I. lnferior to 6 w/o cobalt binder with all carbide being WC. Superior to prior art hardfacings using cast tungsten carbide (combination WC W C).

2. Superior to both prior art cast tungsten hardfacings and typical production of 6 w/o Co, 94 w/o pure WC. 3, 6 w/o iron binder, 94 w/o carbide. Carbide was 81.1 w/o WC, l8.9 wk;

3. About same as 2" above.

superior to both prior art cast tungsten hardfacings and typical production of 6 w/o Co. 94 w/o pure WC.

4. Superior to results in 2" and 3" above, approaching close to best production run using 6 w/o Co, 94 w/o pure WC.


5. Results not as good as for 6 w/o Co, 94 w/o purc WC. about comparable to prior art cast tungsten carbide hardfacings.

5. 6 w/o iron binder, 94 w/o carbide. Carbide was 13 w/o WC, 83 w/o W2C, and 4 w/o free carbon. Mix G-57.

These results reflect that it is possible to obtain superior hardfacings when at least a part of the tungsten carbide is ditungsten carbide, and an iron binder is used. The use of an iron binder has the additional advantage of eliminating the problem of obtaining a supply of the sometimes critical cobalt.

It is not intended that the above example should be construed in a limiting sense, as various sintered tungsten carbides may be applied to the gage surfaces of rolling cutters without departing from the spirit of the invention. Various shapes of carbide granules may be used, although it is believed to be better to avoid sharp corners and slivery shapes, and the binder content may Var /651615 weight percent cobalt or other member of the iron group. Various welding techniques may be used in addition to the oxyacelylene method, e.g., atomic hydrogen. With respect to the matrix, hardfacings using no ferromanganese and ferromolybdenum are satisfactory but not as good as the matrix composition of the example, and more of these powders, e.g., 2.0 percent manganese and 0.5 percent molybdenum, gave a matrix which was generally too hard and brittle, causing a tendency to crumble and disintegrate rapidly. Various other matrix additives may be substituted for the manganese and molybdenum, provided that the resulting matrix is of comparable hardness and toughness, and also provided that the substituted additive is equally effective in preventing dissolution of the tungsten carbide in the matrix.

It may be important that the additives be added to the welding tube as filler flour surrounding the tungsten carbide granules, as attempts to incorporate the same elements in the tube wall itself resulted in hardfacings which were not as satisfactory as those where the elements were added as fillers. The powder surrounding each granule may act as a temporary heat barrier, itself then going into solution with the matrix but in so doing providing a time delay before the granules are surrounded by molten metal. Since by that time the welder will have moved his torch to another area, this time would be quite important.

The hardfacing compositions comprising a mixture of WC and W C sintered with an iron group binder, preferably iron itself, have obvious utility in many additional applications in general wherever effective cutting action, wear resistance, or both, are required.

What is claimed is:

1. In a rolling cutter of a rock bit having a conical gage surface adapted to contact the sidewall of a hole as the cutter rolls over the bottom of such hole, the improvement comprising a hardfacing on said gage surface consisting of sintered tungsten carbide in an alloy steel matrix.

2. An improved gage hardfacing on a rolling cone cutter of a rock bit consisting of granules of sintered tungsten carbide in an alloy steel matrix.

3. An improved gage hardfacing on a rolling cone cutter of a rock bit consisting of granules of sintered tungsten carbide in an alloy steel matrix, said matrix including alloy steel derived from the cutter.

4. An improved gage hardfacing welded on the gage surface of a rolling cutter, consisting of granules of sintered tungsten carbide in an alloy steel matrix, said matrix having a pre-application composition including about 1.0 w/o manganese and 0.25 w/o molybdenum.

5. An improved gage hardfacing on a rolling cutter consisting of sintered tungsten carbide granules in an alloy steel matrix, said sintered tungsten carbide comprising a mixture of monotungsten carbide and ditungsten carbide.

6. An improved gagehardfacing on a rolling cone cutter consisting of sintered monotungsten carbide granules in an alloy steel matrix.

7. The improved gage hardfacing of claim 6 in which the binder for said granules includes at least one iron group metal.

8. The improved gage hardfacing of claim 7 in which said binder is cobalt.

9. The improved gage hardfacing of claim 7 in which said binder is iron.

10. The improved gage hardfacing of claim 7 in which said binder is nickel.

11. The improved gage hardfacing of claim 6 in which the binder for said granules includes at least two iron group metals. I

12. The improved gage hardfacing of claim 6 in which the binder for said granules is metallic and includes at least one iron group metal.

13. An improved gage hardfacing of claim 6 in which the binder for said granules consists of at least two metals, one of said metals being an iron group metal.

14. An improved gage hardfacing on rolling cone cutters, said hardfacing being a weldment of sintered tungsten carbide granules dispersed in an alloy steel matrix, said granules comprising a mixture of monotungsten carbide and ditungsten carbide grains cemented together with a metallic binder including iron.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2407642 *Nov 23, 1945Sep 17, 1946Hughes Tool CoMethod of treating cutter teeth
US2660405 *Jul 11, 1947Nov 24, 1953Hughes Tool CoCutting tool and method of making
US2833520 *Jan 7, 1957May 6, 1958Owen Robert GAnnular mill for use in oil wells
US2887302 *Aug 31, 1956May 19, 1959Dresser Operations IncBit and cutter therefor
US2939684 *Mar 22, 1957Jun 7, 1960Hughes Tool CoCutter for well drills
US3120285 *Feb 1, 1961Feb 4, 1964Jersey Prod Res CoStabilized drill bit
US3165822 *Aug 7, 1963Jan 19, 1965Metal Carbides CorpTungsten carbide tool manufacture
US3279049 *Dec 5, 1963Oct 18, 1966Chromalloy CorpMethod for bonding a sintered refractory carbide body to a metalliferous surface
US3380861 *May 5, 1965Apr 30, 1968Deutsche Edelstahlwerke AgSintered steel-bonded carbide hard alloys
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3946820 *Oct 25, 1974Mar 30, 1976Faurilda Ferne KnappNovel cutter elements for drill bits
US4066422 *Oct 2, 1975Jan 3, 1978Caterpillar Tractor Co.Wear-resistant composite material and method of making an article thereof
US4079163 *Nov 24, 1975Mar 14, 1978Nippon Steel CorporationWeldable coated steel sheet
US4162392 *Jul 13, 1977Jul 24, 1979Union Carbide CorporationHard facing of metal substrates
US4224382 *Jan 26, 1979Sep 23, 1980Union Carbide CorporationHard facing of metal substrates
US4277108 *May 1, 1980Jul 7, 1981Reed Tool CompanyHard surfacing for oil well tools
US4312894 *Jun 13, 1980Jan 26, 1982Union Carbide CorporationHard facing of metal substrates
US4414029 *May 20, 1981Nov 8, 1983Kennametal Inc.Powder mixtures for wear resistant facings and products produced therefrom
US4597456 *Jul 23, 1984Jul 1, 1986Cdp, Ltd.Conical cutters for drill bits, and processes to produce same
US4650722 *Dec 15, 1983Mar 17, 1987Union Carbide CorporationHard faced article
US4666797 *Apr 5, 1984May 19, 1987Kennametal Inc.Wear resistant facings for couplings
US4726432 *Jul 13, 1987Feb 23, 1988Hughes Tool Company-UsaDifferentially hardfaced rock bit
US4814234 *Mar 25, 1987Mar 21, 1989Dresser IndustriesSurface protection method and article formed thereby
US4836307 *Dec 29, 1987Jun 6, 1989Smith International, Inc.Hard facing for milled tooth rock bits
US4938991 *Dec 6, 1988Jul 3, 1990Dresser Industries, Inc.Surface protection method and article formed thereby
US4944774 *Mar 27, 1989Jul 31, 1990Smith International, Inc.Hard facing for milled tooth rock bits
US5201376 *Apr 22, 1992Apr 13, 1993Dresser Industries, Inc.Rock bit with improved gage insert
US5439067 *Aug 8, 1994Aug 8, 1995Dresser Industries, Inc.Rock bit with enhanced fluid return area
US5439068 *Aug 8, 1994Aug 8, 1995Dresser Industries, Inc.Modular rotary drill bit
US5445231 *Jul 25, 1994Aug 29, 1995Baker Hughes IncorporatedEarth-burning bit having an improved hard-faced tooth structure
US5492186 *Sep 30, 1994Feb 20, 1996Baker Hughes IncorporatedSteel tooth bit with a bi-metallic gage hardfacing
US5518077 *Mar 22, 1995May 21, 1996Dresser Industries, Inc.Rotary drill bit with improved cutter and seal protection
US5547033 *Dec 7, 1994Aug 20, 1996Dresser Industries, Inc.Rotary cone drill bit and method for enhanced lifting of fluids and cuttings
US5553681 *Dec 7, 1994Sep 10, 1996Dresser Industries, Inc.Rotary cone drill bit with angled ramps
US5579856 *Jun 5, 1995Dec 3, 1996Dresser Industries, Inc.Gage surface and method for milled tooth cutting structure
US5595255 *Aug 8, 1994Jan 21, 1997Dresser Industries, Inc.Rotary cone drill bit with improved support arms
US5606895 *Aug 8, 1994Mar 4, 1997Dresser Industries, Inc.Method for manufacture and rebuild a rotary drill bit
US5624002 *Apr 13, 1995Apr 29, 1997Dresser Industries, Inc.Rotary drill bit
US5641029 *Jun 6, 1995Jun 24, 1997Dresser Industries, Inc.Rotary cone drill bit modular arm
US5653299 *Nov 17, 1995Aug 5, 1997Camco International Inc.Hardmetal facing for rolling cutter drill bit
US5663512 *Nov 21, 1994Sep 2, 1997Baker Hughes Inc.Hardfacing composition for earth-boring bits
US5667903 *May 10, 1995Sep 16, 1997Dresser Industries, Inc.Method of hard facing a substrate, and weld rod used in hard facing a substrate
US5715899 *Feb 2, 1996Feb 10, 1998Smith International, Inc.Hard facing material for rock bits
US5740872 *Jul 1, 1996Apr 21, 1998Camco International Inc.Hardfacing material for rolling cutter drill bits
US5755297 *Jul 3, 1996May 26, 1998Dresser Industries, Inc.Rotary cone drill bit with integral stabilizers
US5755298 *Mar 12, 1997May 26, 1998Dresser Industries, Inc.Hardfacing with coated diamond particles
US5755299 *Dec 27, 1995May 26, 1998Dresser Industries, Inc.Hardfacing with coated diamond particles
US5791422 *Mar 12, 1997Aug 11, 1998Smith International, Inc.Rock bit with hardfacing material incorporating spherical cast carbide particles
US5791423 *Aug 2, 1996Aug 11, 1998Baker Hughes IncorporatedEarth-boring bit having an improved hard-faced tooth structure
US5836409 *Mar 31, 1997Nov 17, 1998Vail, Iii; William BanningMonolithic self sharpening rotary drill bit having tungsten carbide rods cast in steel alloys
US5944127 *May 5, 1997Aug 31, 1999Smith International, Inc.Hardfacing material for rock bits
US5967248 *Oct 14, 1997Oct 19, 1999Camco International Inc.Rock bit hardmetal overlay and process of manufacture
US5988302 *Jul 31, 1997Nov 23, 1999Camco International, Inc.Hardmetal facing for earth boring drill bit
US6045750 *Jul 26, 1999Apr 4, 2000Camco International Inc.Rock bit hardmetal overlay and proces of manufacture
US6102140 *Jan 16, 1998Aug 15, 2000Dresser Industries, Inc.Inserts and compacts having coated or encrusted diamond particles
US6131676 *Oct 5, 1998Oct 17, 2000Excavation Engineering Associates, Inc.Small disc cutter, and drill bits, cutterheads, and tunnel boring machines employing such rolling disc cutters
US6138779 *Jan 16, 1998Oct 31, 2000Dresser Industries, Inc.Hardfacing having coated ceramic particles or coated particles of other hard materials placed on a rotary cone cutter
US6170583Jan 16, 1998Jan 9, 2001Dresser Industries, Inc.Inserts and compacts having coated or encrusted cubic boron nitride particles
US6196338 *Jan 22, 1999Mar 6, 2001Smith International, Inc.Hardfacing rock bit cones for erosion protection
US6206116Jul 13, 1998Mar 27, 2001Dresser Industries, Inc.Rotary cone drill bit with machined cutting structure
US6220117Aug 18, 1998Apr 24, 2001Baker Hughes IncorporatedMethods of high temperature infiltration of drill bits and infiltrating binder
US6241036Sep 16, 1998Jun 5, 2001Baker Hughes IncorporatedReinforced abrasive-impregnated cutting elements, drill bits including same
US6248149 *May 11, 1999Jun 19, 2001Baker Hughes IncorporatedHardfacing composition for earth-boring bits using macrocrystalline tungsten carbide and spherical cast carbide
US6446739 *Jul 19, 2000Sep 10, 2002Smith International, Inc.Rock drill bit with neck protection
US6458471Dec 7, 2000Oct 1, 2002Baker Hughes IncorporatedReinforced abrasive-impregnated cutting elements, drill bits including same and methods
US6530441 *Jun 27, 2000Mar 11, 2003Smith International, Inc.Cutting element geometry for roller cone drill bit
US6547017 *Nov 16, 1998Apr 15, 2003Smart Drilling And Completion, Inc.Rotary drill bit compensating for changes in hardness of geological formations
US6651756Nov 17, 2000Nov 25, 2003Baker Hughes IncorporatedSteel body drill bits with tailored hardfacing structural elements
US6659206Oct 29, 2001Dec 9, 2003Smith International, Inc.Hardfacing composition for rock bits
US6742611May 30, 2000Jun 1, 2004Baker Hughes IncorporatedLaminated and composite impregnated cutting structures for drill bits
US6766870Aug 21, 2002Jul 27, 2004Baker Hughes IncorporatedMechanically shaped hardfacing cutting/wear structures
US7240746 *Sep 23, 2004Jul 10, 2007Baker Hughes IncorporatedBit gage hardfacing
US7377340 *Oct 29, 2004May 27, 2008Smith International, Inc.Drill bit cutting elements with selectively positioned wear resistant surface
US7510034Oct 11, 2006Mar 31, 2009Baker Hughes IncorporatedSystem, method, and apparatus for enhancing the durability of earth-boring bits with carbide materials
US7568770 *Mar 15, 2007Aug 4, 2009Hall David RSuperhard composite material bonded to a steel body
US7597159Sep 9, 2005Oct 6, 2009Baker Hughes IncorporatedDrill bits and drilling tools including abrasive wear-resistant materials
US7600543 *Jul 13, 2006Oct 13, 2009Sandvik Intellectual Property AbStump grinding disk and wear strips therefor
US7703555Aug 30, 2006Apr 27, 2010Baker Hughes IncorporatedDrilling tools having hardfacing with nickel-based matrix materials and hard particles
US7828089Dec 14, 2007Nov 9, 2010Baker Hughes IncorporatedErosion resistant fluid passageways and flow tubes for earth-boring tools, methods of forming the same and earth-boring tools including the same
US7939142Feb 6, 2007May 10, 2011Ut-Battelle, LlcIn-situ composite formation of damage tolerant coatings utilizing laser
US7946657Jul 8, 2008May 24, 2011Schlumberger Technology CorporationRetention for an insert
US7950746Jun 16, 2006May 31, 2011Schlumberger Technology CorporationAttack tool for degrading materials
US7997359Sep 27, 2007Aug 16, 2011Baker Hughes IncorporatedAbrasive wear-resistant hardfacing materials, drill bits and drilling tools including abrasive wear-resistant hardfacing materials
US8002052Jun 27, 2007Aug 23, 2011Baker Hughes IncorporatedParticle-matrix composite drill bits with hardfacing
US8007051Nov 29, 2007Aug 30, 2011Schlumberger Technology CorporationShank assembly
US8104550Sep 28, 2007Jan 31, 2012Baker Hughes IncorporatedMethods for applying wear-resistant material to exterior surfaces of earth-boring tools and resulting structures
US8136384 *Aug 13, 2008Mar 20, 2012National Oilwell Varco, L.P.Hardband wear testing system and method
US8215420Feb 6, 2009Jul 10, 2012Schlumberger Technology CorporationThermally stable pointed diamond with increased impact resistance
US8252225Mar 4, 2009Aug 28, 2012Baker Hughes IncorporatedMethods of forming erosion-resistant composites, methods of using the same, and earth-boring tools utilizing the same in internal passageways
US8292985Feb 24, 2009Oct 23, 2012Baker Hughes IncorporatedMaterials for enhancing the durability of earth-boring bits, and methods of forming such materials
US8297381Jul 13, 2009Oct 30, 2012Baker Hughes IncorporatedStabilizer subs for use with expandable reamer apparatus, expandable reamer apparatus including stabilizer subs and related methods
US8388723Feb 8, 2010Mar 5, 2013Baker Hughes IncorporatedAbrasive wear-resistant materials, methods for applying such materials to earth-boring tools, and methods of securing a cutting element to an earth-boring tool using such materials
US8403080 *Dec 1, 2011Mar 26, 2013Baker Hughes IncorporatedEarth-boring tools and components thereof including material having hard phase in a metallic binder, and metallic binder compositions for use in forming such tools and components
US8434573Aug 6, 2009May 7, 2013Schlumberger Technology CorporationDegradation assembly
US8464814Jun 10, 2011Jun 18, 2013Baker Hughes IncorporatedSystems for manufacturing downhole tools and downhole tool parts
US8490674May 19, 2011Jul 23, 2013Baker Hughes IncorporatedMethods of forming at least a portion of earth-boring tools
US8540037Apr 30, 2008Sep 24, 2013Schlumberger Technology CorporationLayered polycrystalline diamond
US8567532Nov 16, 2009Oct 29, 2013Schlumberger Technology CorporationCutting element attached to downhole fixed bladed bit at a positive rake angle
US8590644Sep 26, 2007Nov 26, 2013Schlumberger Technology CorporationDownhole drill bit
US8622155Jul 27, 2007Jan 7, 2014Schlumberger Technology CorporationPointed diamond working ends on a shear bit
US8657038Oct 29, 2012Feb 25, 2014Baker Hughes IncorporatedExpandable reamer apparatus including stabilizers
US8657039Dec 3, 2007Feb 25, 2014Baker Hughes IncorporatedRestriction element trap for use with an actuation element of a downhole apparatus and method of use
US8673455 *Apr 18, 2011Mar 18, 2014Ut-Battelle, LlcIn-situ composite formation of damage tolerant coatings utilizing laser
US8714285Nov 16, 2009May 6, 2014Schlumberger Technology CorporationMethod for drilling with a fixed bladed bit
US8758462Jan 8, 2009Jun 24, 2014Baker Hughes IncorporatedMethods for applying abrasive wear-resistant materials to earth-boring tools and methods for securing cutting elements to earth-boring tools
US8834786 *Jun 30, 2010Sep 16, 2014Kennametal Inc.Carbide pellets for wear resistant applications
US8839887 *Mar 12, 2010Sep 23, 2014Smith International, Inc.Composite sintered carbides
US8869920Jun 17, 2013Oct 28, 2014Baker Hughes IncorporatedDownhole tools and parts and methods of formation
US8905117May 19, 2011Dec 9, 2014Baker Hughes IncoporatedMethods of forming at least a portion of earth-boring tools, and articles formed by such methods
US8931854Sep 6, 2013Jan 13, 2015Schlumberger Technology CorporationLayered polycrystalline diamond
US8945720 *Aug 6, 2009Feb 3, 2015National Oilwell Varco, L.P.Hard composite with deformable constituent and method of applying to earth-engaging tool
US8978734May 19, 2011Mar 17, 2015Baker Hughes IncorporatedMethods of forming at least a portion of earth-boring tools, and articles formed by such methods
US8997900Dec 15, 2010Apr 7, 2015National Oilwell DHT, L.P.In-situ boron doped PDC element
US9051795Nov 25, 2013Jun 9, 2015Schlumberger Technology CorporationDownhole drill bit
US9068410Jun 26, 2009Jun 30, 2015Schlumberger Technology CorporationDense diamond body
US20100037675 *Aug 13, 2008Feb 18, 2010Hannahs Daniel LHardband Wear Testing System and Method
US20100230173 *Sep 16, 2010Smith International, Inc.Carbide Composites
US20110031028 *Aug 6, 2009Feb 10, 2011National Oilwell Varco, L.P.Hard Composite with Deformable Constituent and Method of Applying to Earth-Engaging Tool
US20120003488 *Jan 5, 2012Kennametal Inc.Carbide Pellets for Wear Resistant Applications
US20120097455 *Dec 1, 2011Apr 26, 2012Baker Hughes IncorporatedEarth-boring tools and components thereof including material having hard phase in a metallic binder, and metallic binder compositions for use in forming such tools and components
USRE37127 *Aug 19, 1998Apr 10, 2001Baker Hughes IncorporatedHardfacing composition for earth-boring bits
DE2804317A1 *Feb 1, 1978Nov 2, 1978Hughes Tool CoGestaengeverbinder
DE102005039036C5 *Aug 18, 2005Jan 22, 2009Hochtief Construction AgRollenmeißel, insbesondere für Tunnelbohrmaschinen
DE102011101784A1May 17, 2011Jan 5, 2012Kennametal Inc.Carbidpellets für verschleissbeständige Anwendungen
EP0323090A1 *Dec 16, 1988Jul 5, 1989Smith International, Inc.Rock bits
EP0909869A2Aug 14, 1998Apr 21, 1999Camco International Inc.Hardmetal overlay for earth boring bit
WO1996036206A2 *May 9, 1996Nov 21, 1996Dresser IndMethod of hard facing a substrate, and weld rod used in hard facing a substrate
WO1997006339A1 *Jul 29, 1996Feb 20, 1997Dresser IndHardfacing with coated diamond particles
WO2007146168A1 *Jun 8, 2007Dec 21, 2007Baker Hughes IncRotary rock bit with hardfacing to reduce cone erosion
WO2008027484A1 *Aug 30, 2007Mar 6, 2008Baker Hughes IncMethods for applying wear-resistant material to exterior surfaces of earth-boring tools and resulting structures
WO2008097937A2 *Feb 5, 2008Aug 14, 2008Ut Battelle LlcIn-situ composite formation of damage tolerant coatings utilizing laser
U.S. Classification175/374, 428/684, 428/539.5, 428/679
International ClassificationE21B10/08, E21B10/50, C22C29/06, E21B10/46, C22C29/08
Cooperative ClassificationE21B10/50, C22C29/08, E21B10/08
European ClassificationC22C29/08, E21B10/50, E21B10/08
Legal Events
Nov 2, 1988AS01Change of name
Effective date: 19881006
Nov 2, 1988ASAssignment
Effective date: 19881006
May 15, 1984ASAssignment
Effective date: 19840330