Piercing apparatus, plug used for piercing apparatus, and method for producing seamless steel pipe
AssigneeNippon Steel & Sumitomo Metal Corporation
InventorsKazuhiro Shimoda, Tomio Yamakawa, Kouji Yamane, Yuji Inoue, Syusuke Shimooka, Kouji Muramatsu
Life of this patent
Estimating the term…
Abstract
There is provided a piercing apparatus in which the occurrence of an inner surface flaw in a hollow shell is suppressed. A piercing apparatus (10) according to an embodiment of the present invention is the piercing apparatus (10) which pierces a billet (18). The piercing apparatus (10) has a plug (14). The plug (14) has a through hole (30). The through hole (30) extends along the central axis, and allows the central portion of the billet (18) being pierced to pass therethrough.
Claims11
A piercing apparatus for piercing a billet, comprising:
- a plug having a through hole which extends along a central axis of the plug and through which a central portion of the billet being pierced is allowed to pass, and
- a mandrel connected to a rear end of the plug, the mandrel having a connection hole extending on a central axis of the mandrel and connectable to the through hole, a size of the connection hole being equal to or larger than a size of the through hole at a position where the connection hole connects to the through hole.
A method for producing a seamless steel pipe, comprising the steps of:
- preparing a piercing apparatus comprising a plug having a through hole extending along a central axis of the plug and a mandrel connected to a rear end of the plug, the mandrel having a connection hole extending on a central axis of the mandrel and connectable to the through hole, a size of the connection hole being equal to or larger than a size of the through hole at a position where the connection hole connects to the through hole;
- and
- piercing a billet by using the piercing apparatus while a central portion of the billet is allowed to pass through the through hole in the plug.
Dependencies are inferred from the claim text.