Electrode, electrochemical machining apparatus using the electrode, electrochemical machining method, and product machined by the method

An electrode of an electrochemical machining device using a nitric acid aqueous solution as an electrolyte, consisting of:

• a core tube formed of a beta titanium alloy that can maintain a shape thereof without plastic deformation when the shape is deformed;
• and
• a coating formed of an acid-resistant insulating material fixed to an outer periphery of the core tube,
• wherein a tip end of the core tube and the coating are formed into a frusto-conical shape that forms an acute angle relative to an inner surface and an obtuse angle relative to an outer surface, and inclined from the inner surface toward the outer surface at an angle of 11° to 15°,
• the electrode is configured so that the electrolyte flows out of a tip of the core tube and flows along the tip ends, running from the inner surface to the outer surface, and
• the core tube allows a second hole having a direction or a curvature different from that of a first hole formed in a predetermined curvature to be formed in a manner connected to the first hole.