A rotary drill bit for use in drilling holes in subsurface formations comprises a bit body having a leading face and a gauge region, a number of blades formed on the leading face of the bit and extending outwardly away from the axis of the bit so as to define between the blades a number of fluid channels leading towards the gauge region, a number of cutting elements mounted side-by-side along each blade, and a number of nozzles in the bit body for supplying drilling fluid to the fluid channels for cleaning and cooling the cutting elements. In each of the fluid channels, adjacent the gauge region, is an opening into an enclosed passage which passes internally through the bit body to an outlet which, in use, communicates with the annulus between the drill string and the wall of the borehole being drilled. The gauge region of the drill bit comprises a substantially continuous bearing surface which extends around the whole of the gauge region.

Rotary drill bits

In one embodiment, a compact for tools, such as cutting, drilling and shaping tools, consists essentially of self-bonded abrasive particles. The bonded particles define a substantially continuous interconnected network of pores, dispersed throughout the compact. The method for making such a compact comprises the steps of bonding a mass of abrasive particles, aided by a sintering aid material, under high temperatures and pressures (HP/HT) to form an abrasive body comprised of said particles in a self-bonded form and said material infiltrated throughout the body. The body is then treated to remove substantially all infiltrated material, thereby to produce a compact consisting essentially of the self-bonded abrasive particles. In another embodiment, a composite compact which is made in a similar manner to the first embodiment consists essentially of a layer of self-bonded abrasive particle and a substrate layer (preferably of cemented carbide) bonded to the abrasive particle layer.

Temperature resistant abrasive compact and method for making same

The invention is a composite polycrystalline diamond compact comprising at least one layer of diamond crystals and precemented carbide pieces which have been pressed under sufficient heat and pressure to create composite polycrystalline material wherein polycrystalline diamond and the precemented carbide pieces are interspersed in one another. Preferably, this composite material layer is disposed as a transition layer between the layer including the working surface of the compact and the substrate for the compact. In addition, the layer including the working surface may also be comprised of the composite material, with the general requirement that the volume percent of the polycrystalline diamond component in the layer including the working surface be higher than in the transition layer. Alternatively, the compact, rather than being divided into discrete layers, instead comprises a single layer of this composite material wherein the concentration of the polycrystalline diamond component is at its highest at the working surface of the compact and then decreases in the direction away from the working surface.

Composite polycrystalline diamond compact

Disclosed is a polycrystalline diamond or diamond-like element with greatly improved wear resistance without loss of impact strength. These elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The PCD element has a body with a plurality of bonded diamond or diamond-like crystals forming a continuous diamond matrix that has a diamond volume density greater than 85%. Interstices among the diamond crystals form a continuous interstitial matrix containing a catalyzing material. The diamond matrix table is formed and integrally bonded with a metallic substrate containing the catalyzing material during the HTHP process. The diamond matrix body has a working surface, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material. Typically, less than about 70% of the body of the diamond matrix table is free of the catalyzing material.

High volume density polycrystalline diamond with working surfaces depleted of catalyzing material

A roller cone rock bit is disclosed with an improved bearing system. The improvement comprises a main journal bearing which is substantially frustoconically shaped and a main roller cone bearing which is reverse shaped to mate with the journal bearing. The journal and roller cone bearings comprise polycrystalline diamond. The invention also includes a means for retaining the roller cone on the journal.

Polycrystalline diamond bearing system for a roller cone rock bit

Diamond tools and superpressure processes for the preparation thereof are described wherein the diamond content is present either in the form of a mass comprising diamond crystals bonded to each other or of a thin skin of diamond crystals bonded to each other. In each instance the diamond content is supported on and directly bonded to an extremely stiff sintered carbide substrate in order to provide mechanical support therefor to more effectively utilize the high elastic modulus of the diamond.

Diamond tools for machining

Abrasive bodies comprising combinations of cubic boron nitride crystals and sintered carbide are disclosed. These composite bodies are prepared by superpressure processes. Cubic boron nitride contents of up to about 99 volume percent have been successfully employed in certain constructions. Similar abrasive bodies have been prepared from mixtures of cubic boron nitride, diamond and carbide powder.

Cubic boron nitride/sintered carbide abrasive bodies

ALUMINUM ALLOYS OF NICKEL, COBALT, MANGANESE, IRON, VANADIUM AND CHROMIUM HAVE BEEN FOUND TO PROVIDE SUCCESSFUL BONDING MECHANISMS FOR THE PREPARATION OF CUBIC BORON NITRIDE (CBN) COMPACTS. THESE BONDING MEDIA ARE PARTICULARLY EFFECTIVE FOR PREPARING COMPACTS OF CBN CRYSTALS SMALLER THAN ABOUT 30 MICROMETERS IN LARGEST DIMENSION. THE PREPARATION OF TOOL INSERTS MADE OF CUBICBORON NITRIDE CRYSTALS BONDED TO AND SUPPORTED ON A SINTERED CARBIDE MASS IS DESCRIBED WHEREIN SUCH AN ALUMINUM ALLOY IS USED AS THE BONDING MEDIUM.

Abrasive bodies of finely-divided cubic boron nitride crystals

Certain aluminum alloys have been found to be effective catalysts for the synthesis of cubic boron nitride from hexagonal boron nitride. Nickel/aluminum and cobalt/aluminum alloys in particular are very effective catalysts. Composite cubic boron nitride/cemented carbide tool inserts have been prepared utilizing these teachings.

Catalyst systems for synthesis of cubic boron nitride

Reaction vessel construction is provided whereby in the practice of the invention disclosed in U.S. Pat. No. 3,297,407 - Wentorf, Jr. diamond seed material is isolated from the main supply of catalyst-solvent metal by an inert barrier insoluble in the catalyst-solvent bath. One or more restricted diamond growth paths (e.g. small diameter wires of catalyst-solvent) are provided through the inert barrier interconnecting diamond seed material and the main supply of catalyst-solvent metal. In this way the diamond seed material cannot be eroded or destroyed by exposure to the bath of catalyst-solvent metal and a controllable limit can be placed on the size of the single diamond seed crystal ultimately presented to the bath via any given growth path.

William A. Rocco

Papers

Diamond tools for machining

Cubic boron nitride/sintered carbide abrasive bodies

Abrasive bodies of finely-divided cubic boron nitride crystals

Catalyst systems for synthesis of cubic boron nitride

Apparatus and method for isolation of diamond seeds for growing diamonds