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:
Nov. 08, 2011
Filed:
Jun. 19, 2006
Nobusuke Kariya, Kanagawa, JP;
Norio Kanamoto, Chiba, JP;
Hidekazu Ookubo, Chiba, JP;
Yoshiharu Kusumoto, Chiba, JP;
Takeshi Fujita, Hiroshima, JP;
Nobusuke Kariya, Kanagawa, JP;
Norio Kanamoto, Chiba, JP;
Hidekazu Ookubo, Chiba, JP;
Yoshiharu Kusumoto, Chiba, JP;
Takeshi Fujita, Hiroshima, JP;
JFE Steel Corporation, Tokyo, JP;
Abstract
A high carbon cold-rolled steel sheet having both excellent stretch-flange formability and excellent homogeneity of hardness in the sheet thickness direction is provided by a manufacturing method having the steps of: hot-rolling a steel containing 0.2 to 0.7% C by mass at finishing temperatures of (Atransformation point −20° C.) or above to prepare a hot-rolled sheet; cooling the hot-rolled sheet to temperatures of 650° C. or below at cooling rates from 60° C./s or larger to smaller than 120° C./s; coiling the hot-rolled sheet after cooling at coiling temperatures of 600° C. or below; cold-rolling the coiled hot-rolled sheet at rolling reductions of 30% or more to prepare a cold-rolled sheet; and annealing the cold-rolled sheet at annealing temperatures from 600° C. or larger to Atransformation point or lower.