Ultrasonic extrusion apparatus for metal material

An ultrasonic extrusion apparatus for extruding a metal material in such a way that an extrusion die is resonated by ultrasonic vibrations, the ultrasonic extrusion apparatus comprising:

• a die body disposed between an extrusion piston and a die holder;
• front and rear conical surfaces respectively formed on front and rear surfaces of the die body, each of the front and rear conical surfaces being concave;
• an extrusion hole passing through central portions of the front and rear conical surfaces between the front and rear conical surfaces, the extrusion hole being defined by:
• a first inner diameter part through which the metal material is actually extruded;
• and a second inner diameter part having a diameter larger than the first inner diameter part so that the metal material that has passed through the first inner diameter part is prevented from coming into contact with the second inner diameter part;
• and
• a plurality of ultrasonic vibrators mounted to a circumferential outer surface of the die body, the ultrasonic vibrators applying the ultrasonic vibrations to the die body,
• wherein the ultrasonic vibrators are arranged around the circumferential outer surface of the extrusion hole of the die body to be symmetrical based on the extrusion hole so that the ultrasonic vibrations are evenly applied to the die body,
• wherein a plurality of chamfering surfaces are formed on the circumferential outer surface of the extrusion hole of the die body at positions spaced apart from each other at regular intervals with respect to a circumferential direction, a mounting hole is formed in a central portion of each of the chamfering surfaces, and the ultrasonic vibrators are mounted to the respective chamfering surfaces through the corresponding mounting holes.