Title:
METHOD AND DEVICE FOR FORMING LARGE DIAMETER SQUARE STEEL TUBE
Document Type and Number:
Japanese Patent JP2735411
Kind Code:
B2
Abstract:
PURPOSE: To straighten distortion, torsion, etc., of a steel tube, and to exactly shape a cross section of the steel tube by nearly finishing square forming of the steel tube by hot plastic working in preforming, and subsequently, executing finish forming of a square steel tube by cold working.
CONSTITUTION: A forming roll process consisting of plural stages is divided into a preforming roll process 6 and a finish forming roll process 8. In the preforming process, by hot (including warm) working, its cross section shape is formed to a half formed steel tube being approximate to a square steel. tube in which some working amount is left, comparing with a cross section of a complete square steel tube. Before this semi formed steel tube is fed to the finish forming roll process, the whole steel tube is cooled 7 to a temperature in the vicinity of a room temperature, and the remaining working amount is subjected to finish shaping by cold working by the finish forming roll process 8. In such a way, a large diameter square steel tube of a high quality can be obtained.
Inventors:
NAKAJIMA NORIO
NAKAJIMA HIROSHI
NAKAJIMA NORIO
NAKAJIMA SHIN
NAKAJIMA HIROSHI
NAKAJIMA NORIO
NAKAJIMA SHIN
Application Number:
JP20230891A
Publication Date:
April 02, 1998
Filing Date:
July 18, 1991
Export Citation:
Assignee:
NAKAJIMA KOKAN KK
International Classes:
B21C37/15; B21D5/12; C21D8/10; (IPC1-7): B21C37/15; C21D8/10
Domestic Patent References:
| JP3151117A | ||||
| JP1266913A | ||||
| JP61115614A |
Attorney, Agent or Firm:
Yoshihiro Morimoto
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