A solid wear-resistant sintered metallic carbide insert adapted for forcible insertion into an opening in a working face of a drill bit includes a generally polygonal body portion having at least about 12 sides extending between opposite ends thereof, and a head portion on one end of the body portion, the corners formed by the said sides being abraded at the ends of the body portion and tapering inwardly towards the end of the body portion opposite to the said one end thereof, the body portion being insertable into the working face opening for mounting the body portion therein with the head portion exposed at the working face. A drill bit incorporating the insert includes a body having a working face provided with a plurality of generally circular insert openings extending inwardly therefrom, and a plurality of the inserts mounted in the openings, each insert engaging the wall of the opening in which mounted in an interference fit. A method of making the insert includes the steps of molding metallic carbide powder under die pressure to form a molded article including a generally polygonal body portion having at least about 12 sides extending between opposite ends thereof and a head portion on one end of the body portion, the body portion tapering inwardly towards the end thereof opposite to the said one end, sintering the molded article to form a sintered article having concave sides, and abrading the sintered article whereby the corners formed by the sides are abraded at the ends of the body portion and are tapered inwardly towards said opposite end of the body portion, thereby producing an insert having the body portion insertable into the working face opening for mounting the body portion therein with the head portion exposed at the working face.
In an earth boring tool an improved sintered tungsten carbide insert and surface conditioning method to improve retention within an interferringly sized hole and to decrease the frequency of fracture of the inserts. The insert has a randomly varied surface finish that is obtained from abrasive treatment with particles having hardness greater than 9.0 on Mohs' Scale. The particles are selected from the class consisting of silicon carbide, boron carbide, boron, and diamond. The resulting surface has asperities varying from a maximum value, smaller than that formed by grinding, to a minimum value, larger than the mat finish obtained by abrading with aluminum oxide.
An insert for insertion into a bore opening formed within a working face of a tool and a method of making the same. The insert includes a head having an integral body adapted for insertion into the bore. The insert has carbide particles adhered to the insert surface to resist removal of the insert from the bore opening.
