Title:
ROTARY DRAW-BENDING METHOD OF METAL PIPE
Document Type and Number:
Japanese Patent JP2019051532
Kind Code:
A
Abstract:
To provide a rotary draw-bending method of a metal pipe having a preferable appearance by preventing irregular wrinkles from occurring on a bent inner circumferential part.SOLUTION: In a rotary draw-bending method of a metal pipe, a circular arcuate curved surface along an outer circumferential surface of the metal pipe 5 and a groove shaped circular arcuate recessed stripe part 3b concentric with the circular arcuate curved surface are formed on a surface abutted on the metal pipe 5 on a bending roller 3, when a target bending angle of the metal pipe 5 to be bent is set as θ, the circular arcuate recessed stripe part 3b is provided on a portion on and after θ/2 from bend starting point of the bending roller 3 by at least one stripe and, on a bend inner circumferential side of the metal pipe 5 in which the bend is propagated and the bending angle is propagated by θ/2 or more by the arcuate recessed stripe part 3b, at least one stripe of circular arcuate protruded stripe 17 is formed.SELECTED DRAWING: Figure 1
Inventors:
OZAKI YOSHIHIRO
ISHIWATARI AKINOBU
ISHIWATARI AKINOBU
Application Number:
JP2017176398A
Publication Date:
April 04, 2019
Filing Date:
September 14, 2017
Export Citation:
Assignee:
JFE STEEL CORP
International Classes:
B21D7/025
Attorney, Agent or Firm:
Toshihiko Ishikawa