Electrode wire for use in electric discharge machining and process for preparing same

A process for preparing an electrode wire for use in machining a workpiece by means of electric spark discharge, comprising the steps of:

• (a) preparing a core wire of copper clad steel wire having 10 to 70% of the cross-sectional area of said core wire being copper;
• (b) coating said core wire with a zinc layer by electroplating;
• (c) elongating said core wire coated with said zinc layer;
• and
• (d) heating said zinc coated core wire to disperse copper into said zinc layer, thereby converting said zinc layer into a copper-zinc alloy layer having a thickness of from about 0.1 to about 15 microns and an average concentration of zinc of less than 50% but not less than 10% by weight, heating said zinc coated core wire to gradually increase the concentration of zinc within said copper-zinc alloy layer in a radially outward direction thereby forming an integral layer in said copper-zinc alloy layer having a zinc concentration from about 40% to about 50% by weight of said integral layer.

A process for preparing an electrode wire for use in machining a workpiece by means of electric spark discharge, comprising the steps of:

• (a) preparing a core wire of a copper clad steel wire having 10 to 70% of the cross-sectional area of said core wire being copper;
• (b) coating said core wire with a zinc layer by electroplating;
• (c) heating said zinc coated core wire to disperse copper into said zinc layer, thereby converting said zinc layer into a copper-zinc alloy layer having an average concentration of zinc of less than 50% but not less than 10% by weight, heating said coated core wire to gradually increase the concentration of zinc within said copper-zinc alloy layer in a radially outward direction thereby forming an integral layer in said copper-zinc alloy layer having a zinc concentration from about 40% to about 50% by weight of said integral layer;
• and
• (d) elongating said core wire coated with said copper-zinc alloy layer so that the thickness of said copper-zinc alloy layer is from about 0.1 to about 15 microns.

A process for preparing an electrode wire for use in machining a workpiece by means of electric spark discharge, comprising the steps of:

• (a) preparing a core wire of copper clad steel wire wherein a 10 to 70% of cross-sectional area thereof is copper;
• (b) dipping said core wire in a molten zinc bath thereby forming a first copper-zinc alloy layer covering said core wire and a zinc layer on said first copper-zinc alloy layer;
• (c) elongating said coated core wire;
• and
• (d) heating said coated and elongated core wire to disperse copper into said first copper-zinc and zinc layers, thereby converting said zinc layer into a second copper-zinc alloy layer and increasing the zinc concentration in said first copper-zinc alloy layer, whereby the total thickness of said first and second copper-zinc alloy layers is from about 0.1 to about 15 microns, the concentration of zinc within said first and second copper-zinc alloys is gradually increased in a radially outward direction and an integral high zinc concentration is formed in said layer having a first and second copper-zinc alloy layers having a zinc concentration from 40% to 50% by weight of said integral layer.

A process for preparing an electrode wire for use in machining a workpiece by means of electric spark discharge, comprising the steps of:

• (a) preparing a core wire of a copper clad steel wire having 10 to 70% of the cross-sectional area of said core wire being copper;
• (b) dipping said core wire in a molten zinc bath thereby forming a first copper-zinc alloy layer on said core wire and a zinc layer on said first copper-zinc alloy layer;
• (c) heating said coated core wire to disperse copper into said first copper-zinc and zinc layers and thereby converting said zinc layer into a second copper-zinc alloy layer and increasing the zinc concentration in said first copper-zinc alloy layer, whereby the concentration of zinc within said first and second copper-zinc alloy layers is gradually increased in a radially outward direction and said first and second copper-zinc alloy layers include an integral layer having a zinc concentration from about 40% to about 50% by weight of said integral layer;
• and
• (d) elongating said coated core wire so that the total thickness of said first and second copper-zinc alloy layers is within the range of from about 0.1 to about 15 microns.