| 摘要 |
PURPOSE:To attain prolongation of the die service life and others by placing the front end face of a male die in a position retracted from the bearing part of a female die in the container direction and self-specifying a sectional shape of an extruded stock at a position being apart from the bearing part. CONSTITUTION:A bearing part 3 vertical to a die hole 4 of a female die 1 is formed and the front end face of a male die 2 is placed in a position retracted from the bearing part 3 in the container direction. When the stem is moved forward to give a pressing force to a billet of a metallic material M, which flows into the die hole 4 through a metal flow gap 6 and forms a hollow extruded stock B. In that time, the shape of the stock B is self-specified at a space position being apart from the bearing part 3 under conditions of an extrusion speed, pressure, etc. Therefore, wear of the bearing part 3 is prevented to prolong the die service life and forming of special form extruded stocks is performable because the sectional shape is self-specified.
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