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:
Feb. 04, 1986
Filed:
Oct. 24, 1984
Takaaki Toyooka, Handa, JP;
Eiichi Yokoyama, Handa, JP;
Akio Ejima, Taketoyocho, JP;
Yoshitomi Onoda, Kofu, JP;
Kawasaki Steel Corporation, Hyogo, JP;
Abstract
In a method of forming an electric welded steel tube, wherein a hot-rolled sheet is formed into a cylindrical shape, with the central portion thereof being lowered as the forming progresses, and thereafter, subjected to reduction in the circumferential direction of the tube by means of tandem type fin-pass rolls to be finished into the tube, the proper forming condition ranges capable of eliminating occurrence of edge waves in the tube seam edge portion and/or of cambers in the longitudinal direction of the tube by three forming conditions factors including the downhill value D.sub.H (downhill coefficient .eta.) of the hot-rolled sheet, the fin-pass total reduction R of the tandem type fin-pass rolls and the distribution of the fin-pass reduction (the distribution ratio .delta. of the first fin-pass reduction).