Roller cone bits with wear and fracture resistant surface

摘要

Roller cone bits of this invention include a steel bit body having at least one leg extending therefrom. A steel cone is rotatably disposed on the leg. The steel cone includes a plurality of steel cutting elements that each project outwardly a distance therefrom. At least one of the cutting elements comprises a steel base portion that is integral with the cone and that projects a distance therefrom. A cutting element end portion is attached to the base portion and extends therefrom to form a tip of the cutting element. The base and end portions are permanently attached together when the cone and base are in a preexisting rigid state. The cutting element end portion is formed from a wear resistant material having a material microstructure comprising a first phase of grains selected from the group of carbides, borides, nitrides, and carbonitrides of W, Ti, Mo, Nb, V, Hf, Ta, and Cr refractory metals; and a second phase of a binder material selected from the group consisting of Co, Ni, Fe, and alloys thereof.