Title:
METHOD FOR PIERCING BILLET
Document Type and Number:
Japanese Patent JP2000176512
Kind Code:
A
Abstract:
To improve biting property at the time of piercing a billet.
In a method for piercing the billet 1 of a base stock for seamless steel tubes with piercing rolls 3 having a barrel-shaped roll body, after forming a tapered surface 2 whose taper angle is 2-10° and so that the ratio d/D of the diameter d at the tip of the tapered billet to the outside diameter D of the not-tapered part of the billet satisfies the equation: 0.92≤d/D≤0.98, then piercing is executed.
Inventors:
TAKAOKA TATSUO
YAMAZAKI MOTOHARU
ISHIGE TOSHIAKI
YAMAZAKI MOTOHARU
ISHIGE TOSHIAKI
Application Number:
JP35832098A
Publication Date:
June 27, 2000
Filing Date:
December 17, 1998
Export Citation:
Assignee:
NIPPON KOKAN KK
International Classes:
B21B19/04; B21B27/02; (IPC1-7): B21B19/04; B21B27/02
Attorney, Agent or Firm:
Shigeru Takano
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