Verfahren und Vorrichtung zur Verminderung der Wandreibung beim Innenhochdruck-Umformungsprozess

摘要

The invention relates to a method and device for reducing the wall friction during an internal high pressure forming process especially during expansion compression in which a controlled axial feeding of metal into the forming zones occurs after the hollow body which is to be formed is sealed and after the required internal pressure is applied according to the obtained degree of forming. The invention is characterized such that the area of the hollow body which is not to be formed is externally acted upon by pressure on the periphery thereof. The invention also relates to a device for carrying out the method comprising a die in which the hollow body which is to be formed can be placed inside, a sealing and advancing device, and an internal pressure generating system which can be connected to the internal area of the hollow body via a line. The device is characterized in that the part of the die (2, 3) located in the area of the hollow body (1) which is not to be formed has at least one opening on the inner side, said opening being connected to a pressure generating system via a line (13, 13', 14, 14').