摘要:
Displacement members for use in forming a bit body of an earth-boring rotary drill bit include a body having an exterior surface, at least a portion of which is configured to define at least one surface of the bit body as the bit body is formed around the displacement member. In some embodiments, the body may be hollow and/or porous. Methods for forming earth-boring rotary drill bits include positioning such a displacement member in a mold and forming a bit body around the displacement member in the mold. Additional methods include pressing a plurality of particles to form a body, forming at least one recess in the body, positioning such a displacement member in the recess, and sintering the body to form a bit body.
摘要:
Methods for forming bodies of earth-boring drill bits and other tools include milling a plurality of hard particles and a plurality of particles comprising a matrix material to form a mill product comprising powder particles, separating the particles into a plurality of particle size fractions. Some of the particles from the fractions may be combined to form a powder mixture, which may be pressed to form a green body. Additional methods include mixing a plurality of hard particles and a plurality of particles comprising a matrix material to form a powder mixture, and pressing the powder mixture with pressure having an oscillating magnitude to form a green body. In yet additional methods a powder mixture may be pressed within a deformable container to form a green body and drainage of liquid from the container is enabled as the powder mixture is pressed.
摘要:
Geometric compensation techniques are used to improve the accuracy by which features may be located on drill bits formed using particle compaction and sintering processes. In some embodiments, a positional error to be exhibited by at least one feature in a less than fully sintered bit body upon fully sintering the bit body is predicted and the at least one feature is formed on the less than fully sintered bit body at a location at least partially determined by the predicted positional error. In other embodiments, bit bodies of earth-boring rotary drill bits are designed to include a design drilling profile and a less than fully sintered bit body is formed including a drilling profile having a shape differing from a shape of the design drilling profile. Less than fully sintered bit bodies of earth-boring rotary drill bits are formed using such methods.
摘要:
Methods of forming cutter assemblies for use on earth-boring tools include sintering a cone structure to fuse one or more cutting elements thereto. In some embodiments, one or more green, brown, or fully sintered cutting elements may be positioned on a green or brown cone structure prior to sintering the cone structure to a final density. Cutter assemblies may be formed by such methods, and such cutter assemblies may be used in earth-boring tools such as, for example, earth-boring rotary drill bits and hole openers.
摘要:
The residual stresses that are experienced in polycrystalline diamond cutters, which lead to cutter failure, can be effectively modified by selectively thinning the carbide substrate subsequent to high temperature, high pressure (sinter) processing, by selectively varying the material constituents of the carbide substrate, by subjecting the PDC cutter to an annealing process during sintering, by subjecting the formed PDC cutter to a post-process stress relief anneal, or a combination of those means.
摘要:
A superhard cutting element having a polished, low friction, substantially planar cutting face with a surface finish roughness of 10 .mu. in. or less and preferably 0.5 .mu. in. or less.
摘要:
An improved stud design for an earth boring drill bit is disclosed preferably using materials of different hardness and toughness layered to provide maximum resistance to surface abrasion coupled with excellent structural properties including high strength with maximum fracture toughness. The bit body is conventionally attached to a drill string, and has a crown and gage portion. The studs preferably include a core, made of steel or other material having high fracture toughness, covered at least in part with a hard, abrasion resistant material such as tungsten carbide. Each stud is secured to a socket in the bit body by means of brazing or other suitable means such as a press fit. The cutting element is brazed to a mounting face of the stud prior to affixation of the stud to the bit body and is preferably comprised of a polycrystalline diamond compact adhered to a backing layer of tungsten carbide.
摘要:
An improved earth-boring bit the rolling cone variety and an insert for use therein is provided. A superabrasive element is coated with at least one layer of metallic material. The superabrasive element then is placed in a receptacle cavity in a pre-formed hard metal jacket. The superabrasive element then is brazed or infiltrated to the hard metal jacket. Metallurgical and mechanical bonds between the superabrasive element, the at least one layer of metallic material on superabrasive element, the braze or infiltrant binder material, and the fracture-tough material of the hard metal jacket retain the superabrasive element in the cavity of the hard metal jacket. Improved earth-boring bits according to this embodiment of the present invention provide abrasion-resistant earth-boring bits of the rolling cutter variety. Such improved bits, and the inserts therefore, are formed without resort to high-temperature, high-pressure processes.
摘要:
An earth-boring bit has a steel body and bearing pin for rotatably supporting a cone. The cone has an exterior surface containing rows of cutting elements. The cone and cutting elements are formed of cemented tungsten carbide. The cone may be manufactured by applying pressure to a mixture of hard particles and metal alloy powder to form a billet, then machining the billet to a desired over-sized conical shaped product. Then the conical-shaped product is liquid-phase sintered to a desired density, which causes shrinking to the desired final shape.
摘要:
Earth-boring drill bits include a bit body including a blockage-resistant internal fluid passageway. The blockage-resistant internal fluid passageway includes at least one internal fluid passageway formed in the bit body and a cuttings filtering feature formed in the at least one internal fluid passageway configured to prevent at least some cuttings from flowing through the at least one internal fluid passageway. In one embodiment, the cuttings filtering feature includes at least one lateral member extending transversely across the at least one internal fluid passageway. In another embodiment, the cuttings filtering feature includes forming a central portion of the at least one internal fluid passageway with a width along a lateral axis thereof less than an average width of a fluid path extending through a nozzle disposed at least partially within the at least one internal fluid passageway. Methods of forming the blockage-resistant internal fluid passageway are also disclosed.