Patent ID: 7868265

Claim:
A method of manufacturing an electrode wire for wire electric discharge machining including a binary alloy of copper and zinc, the method comprising: hot-extruding an alloy including copper and zinc having an average zinc content per unit volume of 41 to 44%; repeatedly cold-drawing and annealing the hot-extruded alloy to form an electrode wire having a tensile strength of 500 to 650 MPa and an elongation of 15 to 30% at a wire diameter of about 0.9 mm; cold drawing the electrode wire to a diameter of 0.25 mm to 0.30 mm using a continuous slip drawing machine; and annealing the resultant electrode wire; wherein the resultant electrode wire has a tensile strength of 700 to 1040 MPa, and whereby α phase crystals and β′ phase crystals uniformly exist in a nonlayered manner in the resultant electrode wire.