Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Yuichi Yamanari

Yasuyoshi Hidaka

Yasuto Higashida

Yuji Yamamoto

Kazuhiro Shimoda

Yuji Inoue

Kouji Yamane

Tatsuya Miyai

Naoya Shirasawa

Shusuke Shimooka

A piercer plug with increased life and a method of manufacturing it are provided. The piercer plugincludes a tip portionand a trunk portionmade of the same material as the tip portionand continuous to the tip portion. The trunk portionincludes a cylindrical portionhaving a hole used for attaching a bar. The tip portionis harder than the cylindrical portion

Piercer plug and method of manufacturing the same

A method for producing a seamless metal pipe includes the steps of: preparing a billet having a diameter (B); heating the billet; forming, in a center part of a rear end of the heated billet, a hole including four grooves extending in an axial direction of the billet, the grooves each having a groove width (D) satisfying Formula (1), a groove height (H) satisfying Formula (2), and a groove depth (L) satisfying Formula (3); and subjecting the billet provided with the hole to piercing-rolling from a front end thereof by means of a piercing machine. By this means, the generation of burrs and internal defects at the rear end of a hollow shell after piercing-rolling can be suppressed.0.12&#x2264;&#x2264;0.25&#x2003;&#x2003;(1)0.10&#x2264;&#x2264;0.20&#x2003;&#x2003;(2)0.05&#x2264;1/&#x2264;0.10&#x2003;&#x2003;(3)

Method for producing seamless metal pipe

A piercer plug having good base-material deformation resistance is provided. A method of manufacturing a piercer plug () includes the steps of; preparing a plug body () including a tip portion () and a cylindrical portion () having a hole () usable to attach a bar and located rearward of the tip portion (); forming a build-up layer () on the surface of the tip portion (); and heating the plug body () such that the temperature of the tip portion () with the build-up layer () formed thereon is not lower than the austenite transformation temperature and the temperature of the cylindrical portion () is lower than the austenite transformation temperature.

Method of manufacturing piercer plug

Growing community of inventors

Tokyo, Japan

Yuichi Yamanari