PURPOSE: To obtain a sintered hard alloy with high impact resistance by applying a high energy density heat source to the surface of a sintered hard alloy manufactured by powder metallurgy to facilitate refining of WC grains, etc. as well as to reduce internal deffects such as blow holes.

CONSTITUTION: A high energy density heat source such as laser, electron beam or plasma is applied to the surface of a sintered hard alloy manufactured by conventional powder metallurgy and suitable for use as a material for a cutting tool, dies, etc. to remelt the alloy under proper conditions. As a result, internal deffects of the alloy such as fine holes and microcracks are eliminated to enhance the wear resistance, so the tip of a tool made of this alloy is slightly broken in intermittent cutting or hot rolled steel cutting. A throw away tip is also slightly broken owing to a temp. rise in heavy cutting, resulting in a long tool life. In case of throw away, treatment layer 3 may be formed on the rake surface of flank alone of sintered hard alloy 1.