Title:
継目無管の製造方法
Document Type and Number:
Japanese Patent JP5012992
Kind Code:
B2
Abstract:
By using a piercing mill that includes a pusher on the entrance side, a plug on the exit side along a pass line, and a plurality of angled rolls as being provided around the plug so as face to each other, in the case where the maximum diameter of an unsound region consisting of center segregation and porosity in a cross section of a billet is d [mm], piercing-rolling is performed under the condition that the plug nose rolling reduction ratio (TDF) expressed by Formula (1) satisfies Formula (2). TDF = Bd - D ¢ 1 / Bd TDF ¤ - 0.50 × d / Bd + 0.06
In Formulae (1) and (2), Bd is the billet diameter [mm], and D1 is the opening [mm] between the angled rolls at the plug nose position. Thereby, when piercing-rolling is performed, the occurrence of an inner surface flaw attributable to the center segregation and porosity in the billet can be prevented reliably.
Inventors:
Kenichi Saito
Kazumune Shimoda
Tomio Yamakawa
Kazumune Shimoda
Tomio Yamakawa
Application Number:
JP2010273205A
Publication Date:
August 29, 2012
Filing Date:
December 08, 2010
Export Citation:
Assignee:
SUMITOMO METAL INDUSTRIES,LTD.
International Classes:
B21B19/04; B21B23/00; B21B25/00
Domestic Patent References:
| JP2006110590A | ||||
| JP2002361384A | ||||
| JP2002224711A |
Foreign References:
| WO2008062752A1 | ||||
| WO2007116821A1 |
Attorney, Agent or Firm:
Michio Mori
Hideyuki Matsunaga
Hideyuki Matsunaga