An insert for a rock bit that includes tungsten carbide particles, and a cobalt binder disposed around the particles, wherein a grain size of the tungsten carbide particles and a content of the cobalt binder are selected to provide a fracture toughness of at least about 18 ksi (in).sup.0.5, a wear number of at least about 2, and a hardness of 85 to 87 Ra is disclosed.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit under 35 U.S.C. .sctn.120 as a continuation-in-part of U.S. application Ser. No. 10/017,404, filed Dec. 14, 2001 now U.S. Pat. 6,655,478. That application is incorporated by reference in its entirety.
An insert for a rock bit that includes tungsten carbide particles, and a cobalt binder disposed around the particles, wherein a grain size of the tungsten carbide particles and a content of the cobalt binder are selected to provide a fracture toughness of at least about 18 ksi (in).sup.0.5, a wear number of at least about 2, and a hardness of 85 to 87 Ra is disclosed.
