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:
Mar. 16, 2004
Filed:
May. 06, 2002
Tatsumi Kimura, Okayama, JP;
Yasushi Morikage, Chiba, JP;
Keniti Amano, Okayama, JP;
Takanori Okui, Okayama, JP;
Keizou Taoka, Okayama, JP;
Hironori Miura, Okayama, JP;
Hiroyuki Ookubo, Okayama, JP;
Fumimaru Kawabata, Tokyo, JP;
JFE Steel Corporation, Tokyo, JP;
Abstract
When manufacturing a straight steel section having a joint comprising a ball claw and a curved claw by hot-rolling a bloom vertically symmetrically to make a section blank having a flange A at a web end (first step), vertically asymmetrically hot-rolling the section blank to adjust the size of the web and form the flange into a rough joint B including a projection A (second step), and subjecting the projection to hot bend rolling into a curved claw (third step), wherein the bloom has a chemical composition comprising, in mass percentage, from 0.01 to 0.20% C, up to 0.8% Si, up to 1.8% Mn, up to 0.030% P, and up to 0.020% S; and therein the claw bending start temperature in the third step is a temperature of over Ar or up to Ar -50° C., thereby achieving a depth of wrinkle flaws present on the inner surface side of the curved claw of up to 0.5 mm.