ApplicationNo. 07/239162 filed on 08/31/1988
US Classes:175/57, PROCESSES175/426, Insert76/108.2Rock drill
ExaminersPrimary: Neuder, William P.
Attorney, Agent or Firm
International ClassesB22F 3/24 (20060101)
B23P 15/28 (20060101)
E21B 10/46 (20060101)
E21B 10/52 (20060101)
E21B 10/56 (20060101)
AbstractA new and improved tungsten carbide insert for rock bits is disclosed, in which the inserts are subject to extended vibratory tumbling in order to increase their fracture toughness. More specifically the vibratory finishing or tumbling of the inserts has been increased from a typical time of 30-60 minutes to time periods of at least 90 minutes and preferably a minimum of 225 minutes. A marked improvement in toughness is obtained by this process because the size and distribution of surface flaws of the inserts were greatly reduced, and because the surface hardness of the inserts was increased, thereby resulting in an increase in the stress required to cause fracture, and a consequent increase in resistance to breakage.