Cutter combination for an electric shaver

摘要

A cutting device for an electric shaver comprising an outer cutter and a plurality inner blades that are made of a ferrous alloy comprising a substrate of an Fe-Cr stainless steel and a hardened layer of improved hardness and wear resistance. The substrate has a Vickers hardness of 400 or more. The hardened layer has a Vickers hardness of at least 700 and a thickness of 2 to 15 mu m. In particular, it is preferred that the hardened layer is a diffusion layer comprising at least 90 vol % of intermetallic compounds of Al and Fe relative to a total volume of the diffusion layer, and Al content included within a depth of at least 2 mu m of the diffusion layer is 35 to 65% by weight based upon total weight of a region of the diffusion layer ranging up to the thickness of at least 2 mu m. When the ferrous alloy is polished to form the outer cutter and inner blades, it is possible to provide sharp cutting edges of the outer cutter and inner blades, while preventing the occurrence of burrs or micro-chippings at the cutting edges.