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1. (WO2015044094) PIERCING MANDREL HAVING AN IMPROVED SERVICE LIFE FOR PRODUCING SEAMLESS TUBES

Pub. No.:    WO/2015/044094    International Application No.:    PCT/EP2014/070153
Publication Date: Fri Apr 03 01:59:59 CEST 2015 International Filing Date: Tue Sep 23 01:59:59 CEST 2014
IPC: B21B 25/00
Applicants: VALLOUREC DEUTSCHLAND GMBH
Inventors: BRAUN, Winfried
KLEMPEL, Christian
BAADJOU, Rene
KÜMMERLING, Rolf
Title: PIERCING MANDREL HAVING AN IMPROVED SERVICE LIFE FOR PRODUCING SEAMLESS TUBES
Abstract:
The invention relates to a piercing mandrel (4) for piercing heated round blooms (3) made of metal, in order to produce seamless tubes (6), said piercing mandrel comprising a piercing mandrel nose (4.2) and a piercing mandrel main body (4.1) that can be connected to a mandrel bar (5). According to the invention, the external diameter of the piercing mandrel nose (4.2) is conically tapered in the longitudinal direction towards the piercing mandrel main body (4.1), in order to increase the service life of the piercing mandrel when cross-roll piercing round blooms made of metal, in particular made of more highly alloyed steel materials that are difficult to form, while taking into consideration a qualitative improvement of the inner surface of the pierced round blooms, and while reducing the cost of tools.