| 摘要 |
924,287. Extruding. SVENSKAMETALL VERKEN A. B. Nov. 16, 1961 [Dec. 6, 1960], No. 41095/61. Class 83 (4). In a hot or cold-extrusion press having a cylindrical chamber 1, a fixed die 2 at one end and a movable ram 9 at the other end, there is provided between the ram and billet 6 a spherical or part spherical member 7, the maximum cross-sectional area of which is greater than the maximum cross-section of the mouth of the die, and which transmits the ram pressure to the billet. The pressure member 7 is preferably of a softer material than that of the chamber wall, In a modification, a shoulder (not shown) is provided in the conical portion 10 of the ram which seats a sealing ring. It is stated that the use of a spherical or part spherical member distributes the ram pressure so that the maximum force is applied along the billet axis, which creates a new flow pattern in the material which prevents the inclusion of oxides beneath the surface of the extruded rod ; it also results in a residue which is easier to clear from the chamber. |
