| 摘要 |
PURPOSE:To prevent oxidized scales from flowing into an extruding material and to improve a quality of the extruded material, by providing annular projections around an extruding hole of the pressing surface of a die, and extruding a material, in an indirect extrusion of the metallic material by using a cylindrical pressure vessel. CONSTITUTION:A billet 3 of metallic material heated to the high temperature is inserted into a cylindrical pressure vessel (container 1) closed at its one end with a blocking plate 2. To a die holder 5 provided to the tip of a stem 4 which presses the billet 3 and to the pressing surface of a die 6 which contacts with the billet 3, annular projections 6b and 6c formed concentrically with respect to an extruding hole 6a of the die 6 are provided respectively, to press the billet 3. Thus the metallic material 3 is extruded through the hole 6a by leaving the outer peripheral layer of the billet 3 to the inner peripheral surface of the container 1 as a shell 7. In this case, a relative sliding between the end surface of the billet 3 and the die 6 are prevented by the provided annular projections 6b and 6c, then oxidized scales stuck to the billet 3 are prevented from flowing into the material to be extruded. |
