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Patent Searching and Data


Title:
MANUFACTURE OF SEAMLESS STEEL PIPE EXCELLENT IN DURABILITY OF PLUG
Document Type and Number:
Japanese Patent JPH08117815
Kind Code:
A
Abstract:

PURPOSE: To improve the durability of a piercing plug in manufacture of a seamless steel pipe and to prolong its life.

CONSTITUTION: A hollow base stock is made by hot piercing a billet consisting of alloy steel with the piercing plug and the seamless steel tube is manufactured by rolling the obtained hollow base stock. Before executing hot piercing with the plug, a steel plate is preliminarily joined to at least the tip face on the side to be pierced of the billet so as not to be projected to the outside of the outer peripheral face of the billet in the longitudinal and orthogonal directions of the billet and the cross-sectional area C of the steel plate satisfies the next formula. S×0.2≤C≤S×1.2... Formula. Where, S: (the radius of the bottom part of the plug)2×number π, C: the cross-sectional area of the steel plate.


Inventors:
Katsumura, Tatsuro
Minami, Yusuke
Yasukawa, Masahiko
Application Number:
JP1994000278460
Publication Date:
May 14, 1996
Filing Date:
October 18, 1994
Export Citation:
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Assignee:
NKK CORP
International Classes:
B21B15/00; B21B19/04; B21B25/04; B21B45/00; B21B3/02; B21B17/08; (IPC1-7): B21B19/04; B21B15/00; B21B45/00