The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 2016
Filed:
May. 24, 2013
Jfe Steel Corporation, Tokyo, JP;
Toyohisa Shinmiya, Fukuyama, JP;
Kazuhiko Higai, Chiba, JP;
Yuji Yamasaki, Fukuyama, JP;
Katsuhiro Ochi, Fukuyama, JP;
JFE Steel Corporation, , JP;
Abstract
A method of manufacturing a pipe with different diameters along a longitudinal direction that has a small diameter portion, a large diameter portion, and a diameter-changing portion provided between the small diameter portion and the large diameter portion and is formed by press forming a blank made of a metal sheet includes press forming the blank with a U-shape forming die into a U-shaped formed part and press forming the U-shaped formed part with an O-shape forming die set into a circular cross-section formed part. A length of a vertical wall of the U-shape forming die is longer than a length of a vertical wall portion of the U-shaped formed part. In the O-shape forming die set, a die mating line is inclined downwardly, and a ratio t/D of a sheet thickness t of the blank to a diameter D, which represents a diameter of a portion of the O-shape forming die set corresponding to the small diameter portion and a diameter of a portion of the O-shape forming die set corresponding to the large diameter portion, is 0.010≦t/D≦0.080.