Cutting tool insert

Abstract

A hard metal insert for a drill bit is disclosed having an outer body and an encapsulated inner body. The particle size and the chemical composition of the outer body and the inner body are such that the outer body is harder and more wear resistant than the inner body and the inner body is tougher than but not as hard as the outer body. The dimension of the outer body is approximately of equal thickness to the inner body at the cutting surface of the insert to ensure maintaining even wear. A method for forming a hard metal insert is also disclosed comprising creating an inner body mixture of a carbide material with a binder material, creating an outer body mixture of a carbide material with a binder material, compressing the inner body mixture to form the inner body, compressing the outer body mixture around the inner body such that the insert formed has an outer body of approximately equal thickness around the inner body at the cutting surface and sintering the inner and outer bodies so as to create a blending of the homogeneous materials of the two bodies without having any separation therebetween or an interface layer.

Dependencies are inferred from the claim text.