公开(公告)号：EP1336438A4

公开(公告)日：2004-06-09

申请号：EP01970204

申请日：2001-09-25

申请人： NAKAYAMA CORP

发明人： ISHIKAWA TSUYOSHI ,  TSUKADA YOSHIYA ,  SUZUKI RYOICH ,  ISHIKAWA AKIHIRO ,  ISHIKAWA MOTOYOSHI ,  ISHIKAWA JUN

IPC分类号： B21C1/22 ,  B21C3/08 ,  B21C37/20 ,  B21D15/02 ,  B21H1/20 ,  B21H7/18 ,  B21C37/06 ,  B21C37/15 ,  B21D17/04 ,  B21H7/14

CPC分类号： B21C1/27 ,  B21B13/10 ,  B21B17/00 ,  B21C1/22 ,  B21C3/08 ,  B21C37/202 ,  B21D15/02 ,  B21H1/20 ,  B21H7/187 ,  F16L9/02

摘要： A method of forming a cold diametrally reducing roll for metal pipe and a metal pipe formed by the method; the method, characterized by comprising the steps of pre-forming an original pipe formed of a metal pipe to a metal pipe having an elliptic, elongated, or rectangular cross section by a pre-forming roll and forming the pre-formed metal pipe by diametrally reducing the outer peripheral length thereof to less than the outer peripheral length of the original pipe while re-forming the cross sectional shape of the pre-formed metal pipe to a circular shape or the other cross sectional shape different from the cross sectional shape of the pre-formed metal pipe by using a cold diametrally reducing roll disposed on the downstream side of the pre-formed roll.