Method and tool for the cold forging of internally profiled tubes

Abstract

A method and tool for cold forging or cold hammering of internally profiled tubes, whereby a forging blank (2) is while rotated, forged by the action of a number of forging hammers (4), whereby the workpiece (2) as a result of material displacement is formed around a profiling mandrel (3). Before cold forging, the mandrel (3) is adjusted with its axial center (c--c) to a position axially to the side of the forging blank's (2) axial center (c'--c') at a distance equal to half the rolled billets extension during cold forging, and in the direction away from the forging hammers' start position. The apparatus comprises an end socket (5) and a driver (10) between which both the workpiece (2) and mandrel (3) are arranged to be clamped. The end socket (5), which is positioned at the forging hammers (4) starting side, is arranged to include varying thicknesses of end positioners (9) for adjusting the mandrel (3) position, and at the other end of the mandrel is a device for forcing the mandrel against the end socket (5). This spring device is active between a ram (14) and driver (10), which in turn is axially displaceable against the action of a pre-determined pressure.