| 摘要 |
1429002 Extrusion UNITED KINGDOM ATOMIC ENERGY AUTHORITY 5 March 1974 [16 March 1973] 12847/73 Heading B3P A method of extruding a billet comprises urging the billet into a deformation zone provided with a die orifice and rotating the billet to cause extrusion through the orifice. The billet 1 is urged into a deformation zone defined by a primary die 3 either by hydrostatic or mechanical pressure. The primary die is provided with one or more secondary dies (29), Fig. 2 (not shown). The rotation is effected by a rotatably driven mandrel 9 provided with a non-circular, e.g. square, section tip 10 in the deformation zone of the primary die 3. The billet 1 is forced on to the tip before the mandrel is driven so that the billet can be rotated to bring it into engagement with the secondary die 29. The drive is effected from a motor 18 through a chain to a sprocket 20 keyed to a sleeve 14 to which the mandrel is releasably keyed. The billet is constantly urged on to the mandrel by hydrostatic pressure in the chamber 2. The primary die 3 may also be rotated in opposition to the rotation of the billet 1. The billet may be copper but if metals with a galling effect are used a cap may be provided around the base of the mandrel tip. The mandrel may have radiused fillets and the primary die 3 may have friction reducing liners to aid rotation of the billet. Several billets may be extruded successively on to the residue of the previous billet. Alternatively the residue may be removed by an hydraulic ejector 23 after removal of the upper part 11 of the mandrel. |
