PURPOSE: To enhance the wear resistance and melt sticking resistance of parts of a sintered hard alloy obtd. by binding WC and a B-1 type solid soln. as hard phases with an iron group metal by holding the parts under prescribed conditions of temp., time and partial pressure of N2 to enrich the solid soln. in the surface layer of the alloy.

CONSTITUTION: Molded parts of a sintered hard alloy obtd. by binding WC and a B-1 type solid soln. as hard phases with an iron group metal are held at 1,200W1,600°C for 10minW5hr in an atmosphere under 1W700Torr partial pressure of N2 to regulate the binding metal content of the surface layer of the alloy having at least 1μm depth to ≤40% of that of the internal part and to increase the solid soln. content of the surface layer to <80vol%. Thus, a sintered hard alloy with superior wear resistance and melt sticking resistance is obtd.