CARBIDE INSERT FOR USE IN DRILLING TOOL Russian patent published in 1996 - IPC

FIELD: rock cutting tools. SUBSTANCE: carbide insert consists of central part and shell embracing the central part. In so doing, central part over the entire length of the insert is made with high content of bonding metal, and embracing shell has content of bonding metal rising towards periphery of insert. The shell additionally contains boron whose content also rises towards the insert periphery. Width of insert central part amounts to 0.05-0.60 of the insert width and boron content in bonding metal rises in shell thickness, respectively, from 0.001 in bonding metal on the internal surface of shell up to 0.02-0.07 mas.% in bonding metal on its external surface. EFFECT: perfected design of carbide insert due to introduction into shell of alloying element boron to enhance cyclic stability and service life of the insert. 2 dwg, 1 tbl