Title:
METHOD FOR ROLLING TUBE STOCK FOR SEAMLESS TUBE
Document Type and Number:
Japanese Patent JP3400272
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent generation of defects such as crack in the end part of a tube stock and the like due to δ ferrite at the time of piercing rolling of cast billet for seamless tube with a piercer by rolling billet under satisfying specified condition so as not to allow δ ferrite to appear in the metallic structure of tube stock.
SOLUTION: Billet of high chrome alloy containing ≥9wt.% Cr is rolled under a constitution satisfying the inequalities 0.1≤EA≤1.6, EA≤0.075T-89.9, EA≤-0.03T+39.1, and 1200≤T≤1300. In these inequalities, EA: average strain velocity of billet=(dE/dt) (sec-1), E: strain of billet=1n (So/S) (-), So: sectional area of billet at the inlet of piercer(cm2), S: sectional area of billet at the outlet of piercer(cm2), t: time (sec), and T: temperature of billet at the heating furnace (°C). The strain velocity EA is set at a suitable value by adjusting sectional size of tube stock billet, inclination angle of roll of piecer, opening of roll and number of revolution of roll.
Inventors:
Ken Shimamoto
Yukio Miyata
Kita Masaharu
Yukio Miyata
Kita Masaharu
Application Number:
JP34779796A
Publication Date:
April 28, 2003
Filing Date:
December 26, 1996
Export Citation:
Assignee:
Kawasaki Steel Co., Ltd.
International Classes:
B21B19/04; C22C38/00; C22C38/18; (IPC1-7): B21B19/04; C22C38/00; C22C38/18
Domestic Patent References:
| JP63281705A | ||||
| JP8229606A |
Attorney, Agent or Firm:
Yoshio Kosugi (1 person outside)
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