Title:
MANUFACTURE OF SEAMLESS TUBE
Document Type and Number:
Japanese Patent JPH01181905
Kind Code:
A
Abstract:
PURPOSE:To simply prevent generation of inside flaws of a hollow tube stock and to improve the inside quality and yield by specifying a shape of a central hole previously pierced in the top part of a billet and piercing conditions. CONSTITUTION:As for a pierce rolling method by a piercer which pierces a stock 2 by use of two rolls 1, 1 and a plug 6, a ratio of an inlet hole diameter (d)/a stock diameter DB is set to be >=0.45 for hole forming in the top central part of a billet 2 before piercing. Further, a ratio of a hole depth H/the DB is set to be >=0.35. A ratio of X/DB is set to be 0<=X/DB<=0.3, where X(mm) is a distance (grip length) from the stock 2 is bitten by the rolls 1, 1 and abuts on the plug 6. Hence, generation of inside flaws of a hollow tube stock is prevented and the inside quality and yield of products are improved.
Inventors:
ATSUMI TAKUYA
YAMAMOTO KENICHI
KANARI SHOHEI
TAKADA ISAO
MOCHIZUKI RYOSUKE
YAMAMOTO KENICHI
KANARI SHOHEI
TAKADA ISAO
MOCHIZUKI RYOSUKE
Application Number:
JP701688A
Publication Date:
July 19, 1989
Filing Date:
January 18, 1988
Export Citation:
Assignee:
KAWASAKI STEEL CO
International Classes:
B21B19/04; B21B23/00; (IPC1-7): B21B19/04; B21B23/00
Domestic Patent References:
| JPS62114722A | 1987-05-26 |