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. 17, 2004
Filed:
Dec. 12, 2001
JFE Steel Corporation, , JP;
Abstract
The present invention provides a high tensile cold-rolled steel sheet having superior ductility, strain age-hardening characteristics, and crash resistance properties, and also provides a manufacturing method therefor. As a particular means, a thin cold-rolled steel sheet containing 0.05% to 0.30% of C, 0.4% to 2.0% of Si, 0.7% to 3.0% of Mn, 0.08% or less of P, 0.02% or less of Al, and 0.0050% to 0.0250% of N on a mass % basis is manufactured in which N/Al is 0.3 or more. This thin cold-rolled steel sheet is heated to a temperature between (an Ac transformation point) and (an Ac transformation point+50° C.), is cooled at a cooling rate of 5 to 150° C./second in the range of at least 600 to 500° C., and is held in the temperature range of 350 to 500° C. This steel sheet has superior ductility, strain age-hardening characteristics having a &Dgr;TS of 50 MPa or more, and crash resistance properties.