Arrangement for the piercing of a block by means of piercing punch in the pickup of a metal extrusion press

摘要

1485328 Billet piercing; extruding SCHLOEMANN-SIEMAG AG 21 Nov 1975 [6 Dec 1974] 47954/75 Headings B3H and B3P A method of piercing an extrusion billet 4 comprises inserting the billet into the container 2 of an extrusion press, piercing the billet by means of a piercing mandrel 8 against a sealing plate 5 which has a central recess 6 facing the container, the mandrel entering the recess at the end of the piercing stroke, and the recess having dimensions corresponding to those of a die (7). Fig. 2 (not shown), through which the billet is to be extruded to form a tube with a sealed end. The piercing mandrel forms a boss 9 on the end of the billet and the die (7) is fitted over the boss prior to extrusion. To prevent rupturing of the boss at the commencement of extrusion, the mandrel 8 is initially held stationary, e.g. for about 2-3 seconds after which it moves with the extruded stock.