20140283577 | EXTRUSION DIE FOR FORMING HOLLOW MATERIAL - An extrusion die is provided with a male die through which a billet is extruded from an upstream side to a downstream side and, the male die adapted for forming an inside shape of a hollow material; and a female die for holding the male die and forming an outside shape of the hollow material. The male die is formed of a spider and a holder for holding the spider. The spider is formed of a mandrel and a plurality of bridge parts for supporting the mandrel, and enabling a distal-end outer peripheral surface to engage with a bridge-holding surface. The distal-end outer peripheral surface of each of the bridge parts and the bridge-holding surface of the holder are joined by shrink-fitting. | 09-25-2014 |