| 摘要 |
A die holder has adjacent to its front end an annular step portion comprising a steep wall and a gradual wall tapered from the steep wall to the front end, the annular step portion being adapted to provide an annular space between the step portion and an inner surface bounding a billet receiving bore in a container when the die holder is inserted in the bore. During indirect extrusion, foreign impurities such as dirt, lubricant, metal oxides, and the like deposited between the bore surface and the billet are trapped and collected in the annular space against entrainment into an extruded product being formed. An annular ring partly defining the steep wall acts as a barrier that prevents the impurities from getting therepast and minimizes skull formation on the bore surface. An annular butt formed by accumulations of the impurities in the annular space and a butt end of the billet are removed from the container by means of a shear.
|
