초록 ▼

A cladding process is disclosed wherein hard carbide cutter inserts, as well as polycrystalline diamond composites, are metallurgically bonded into an exterior core of a rock bit cone or a drag bit body. The cladding is bonded onto the exterior surface of the core of the cone or the drag bit by a po

A cladding process is disclosed wherein hard carbide cutter inserts, as well as polycrystalline diamond composites, are metallurgically bonded into an exterior core of a rock bit cone or a drag bit body. The cladding is bonded onto the exterior surface of the core of the cone or the drag bit by a powder metallurgy process. A thin layer or coating of a suitable metal, preferably nickel, is provided on, for example, the carbide inserts, prior to mounting into the core. The coating prevents degradation of the carbide through loss of carbon into the core during the powder metallurgy process and accommodates mismatch of thermal expansion between the cutter insert and the core.

대표청구항 ▼

A cutter member of a rock bit, comprising: a core, including an interior opening, wherethrough the cutter member may be mounted to a pin connected to a drill string, said core also including, on its exterior surface, a plurality of cavities; a plurality of hard cutter inserts, the cavities and the c

A cutter member of a rock bit, comprising: a core, including an interior opening, wherethrough the cutter member may be mounted to a pin connected to a drill string, said core also including, on its exterior surface, a plurality of cavities; a plurality of hard cutter inserts, the cavities and the cutter inserts having substantially matching dimensions so that the cutter inserts are accommodated in the cavities without substantial interference; a cladding disposed on the exterior surface of the core, the cladding having been deposited by a powder metallurgy technique including a step wherein compacted powder of the cladding is heated to metallurgically bond said powder to the core, the cladding being substantially harder than the core, said cladding partially embedding the cutter inserts and metallurgically bonding said inserts to the core and to the cladding, and means disposed on the cutter inserts for substantially preventing diffusion of carbon from the cutter inserts into the core and the cladding during the step wherein compacted powder of the cladding is heated to metallurgically bond the same to the core. A process for making a cutter member of a rock bit of the type mounted through a pin to a drill string, the cutter member having a plurality of tungsten-carbide cutter inserts, the process comprising the steps of: depositing a thin layer of a material selected from a group consisting of graphite, copper, copper alloys, silver, silver alloys, cobalt, cobalt alloys, tantalum, tantalum alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, nickel, and nickel alloys on the cutter inserts; after said step of depositing, placing a plurality of the cutter inserts into cavities formed in the outer surface of the solid core of the cutter member, said cavities being dimensioned to accept the cutter inserts without substantial interference; depositing a suitable powder composition on the outer surface of the core so as to partially embed the cutter inserts, and heating and pressing the powder in a suitable mold to metallurgically bond said powder and said cutter inserts to the member and thereby to provide an exterior cladding of the cutter member, said cladding having a hardness of at least 50 Rockwell C units, substantially conforming to the desired final exterior configuration of the cutter member, and being comprised of a material selected from a group consisting of metals and cermets.