Patent ID: 8128867
Filing Date: 2012-03-06
Classification: B22F,C22C

Abstract:
1. A method for producing a cemented carbide material comprising a surface layer and a core that has a grain size gradient structure where the mean hard grain size of the surface layer is larger than that of the core, and a concentration gradient of binder metal wherein the concentration of the binder metal in the surface is smaller than that of the core, comprising the steps of: subjecting a WC—Co system compact to a treatment for producing M subjecting the resulting WC—Co compact containing M subjecting the carburized compact to liquid phase sintering at a temperature of more than 1350° C. to form a sintered body; and coating a surface layer of the sintered body with a compound containing boron and/or silicon and subjecting the coated sintered body to a diffusion heat treatment at a temperature within a range from 1200 to 1350° C.