Electrical discharge machining electrode wire and manufacturing method for same

A method for manufacturing an electrical discharge machining electrode wire comprising a core comprising copper or a copper alloy and a covering layer covering a periphery of the core and including zinc, the method comprising:

• plating the core with a zinc or a zinc alloy once;
• drawing the plated core;
• and
• after the thawing and then winding the plated core onto a bobbin, heat treating in a heat treatment condition under which the covering layer comprises an inner layer including a γ-phase of copper-zinc based alloy and an outer layer including an ε-phase of copper-zinc based alloy and coveting a periphery of the inner layer, an x-ray diffraction intensity of (0001) of the ε-phase is more than twice an x-ray diffraction intensity of (332) of the γ-phase, and the heat treatment condition is in a range from 100° C. to 120° C. for 3 hours to 24 hours,
• wherein an amount of warpage from an axis along a vertical direction is not less than 40 mm/m and not more than 80 mm/m when the electrical discharge machining electrode wire is suspended vertically after annealing with wound onto the bobbin.