| 摘要 |
A rotary drill bit and process of fabrication in which internal fluid passages and watercourses of the bit are lined with a hard metal matrix material which renders the fluid passages more resistant to the erosive forces of the drilling fluid is provided. Also, elements such as lands for cutter element mountings, sockets, ridges, shoulders and the like on the exterior surface of the bit can be fabricated of a hard abrasion and erosion resistant material and incorporated into the bit body during fabrication. The process includes the steps of providing a hollow mold for molding at least a portion of the drill bit and positioning one or more flexible or moldable tubular elements which correspond to the internal watercourses in the mold. The elements are fabricated of a hard metal powdered material dispersed in a polymeric binder. A bit blank is then positioned at least partially within the mold and the mold packed with a metal matrix material which forms the body of the bit. The metal matrix material and the tubular elements are infiltrated with a binder in a furnace to form the bit, with the heat from the furnace burning out the polymeric binder in the tubular elements.
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