Title:
PRODUCTION OF LARGE SIZED SQUARE STEEL TUBE AND LARGE SIZED ROUND STEEL TUBE
Document Type and Number:
Japanese Patent JP3202145
Kind Code:
B2
Abstract:
PURPOSE: To provide the production method of large sized square steel tube and large sized round steel tube in which whole cross section is homogeneous and ductile and which has good elongation, almost no residual stress and enough toughness.
CONSTITUTION: A tube stock 1 heated at a heating furnace 12 is hot formed with a round steel tube forming mill 20 to a finished tube stock 1A by which a final large sized square steel tube is finished in a prescribed dimension, the finished tube stock 1A is hot rolled with a large sized square forming mill 25 to a large sized square steel tube 3 having bulged flat part, after the large sized square steel tube 3 is cooled on a cooling floor 28 and the flat part is shrunk to straight, the prescribed thickness/length large sized square steel tube 3 is obtained by cutting/removing the formed defect part of end part with cutting devices 35, 36. The tube stock 1 heated at heating furnace is hot formed with a round steel tube forming mill 20 to a large sized round steel tube 3, the prescribed diameter, thickness and length large sized round steel tube 3 is obtained by executing cooling, cutting and removing.
Inventors:
Norio Nakajima
Application Number:
JP9905195A
Publication Date:
August 27, 2001
Filing Date:
April 25, 1995
Export Citation:
Assignee:
Nakajima Steel Pipe Co., Ltd.
International Classes:
B21C37/08; B21C37/15; (IPC1-7): B21C37/08; B21C37/15
Domestic Patent References:
| JP397810A | ||||
| JP441006A | ||||
| JP6248342A |
Attorney, Agent or Firm:
Yoshihiro Morimoto