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Title:
HIGH EXPANSION ROLLING METHOD OF SEAMLESS TUBE
Document Type and Number:
Japanese Patent JPH07241606
Kind Code:
A
Abstract:

PURPOSE: To suppress the variation of the outside diameter of tube in the longitu dinal direction after rolling by making the lead angles of rolling rolls during rolling the tip part of a material to be rolled smaller than the lead angles of rolling rolls during rolling the stational part in high expansion rolling.

CONSTITUTION: An arithmetic and control circuit 40 controls roll case tilting devices 42 of rolling rolls 31A, 31B through a roll case tilting circuit 41 and controls the lead angles β of the rolling rolls 31A, 31B. The arithmetic and control circuit 40 calculates the advance amount of tube with the rolling rolls 31A, 31B after detecting the start of biting the tip of a hollow tube stock 32A and operates the time for rolling the tip of tube having a prescribed length that is predetermined and the time for rolling the stational part of tube thereafter. In this way, the arithmetic and control circuit 40 controls the lead angles βof the rolling rolls 31A, 31B at the time of rolling the tip of tube to the stational part of tube. And the lead angles β at the time of rolling the tip of tube are made smaller than the lead angles β at the time of rolling the stational part of tube. In this way, the outside diameter in the tip of tube is reduced and expansion is suppressed.


Inventors:
Yorifuji, Akira
Shimizu, Tetsuo
Toyooka, Takaaki
Application Number:
JP1994000058308
Publication Date:
September 19, 1995
Filing Date:
March 04, 1994
Export Citation:
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Assignee:
KAWASAKI STEEL CORP
International Classes:
B21B19/08; (IPC1-7): B21B19/08