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. 17, 1994
Filed:
Dec. 23, 1992
Applicant:
Inventors:
Assignee:
Kawasaki Steel Corporation, , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C / ; C21D / ;
U.S. Cl.
CPC ...
148326 ; 148602 ; 148654 ;
Abstract
A low-yield-ratio high-strength hot-rolled steel sheet having the advantageous features of both conventional precipitation-strengthened steel and structure-strengthened steel and free from the drawbacks of these conventional steels, and a manufacturing method characterized in hot-rolling such a steel sheet. The steel sheet has an upper limit of C content of about 0.18 wt. %, and the lower C content limit approximately satisfies C.gtoreq.0.05+Ti/4+Nb/8 in relationship with the content of Ti and/or Nb. The steel sheet also contains about 0.5 to 2.5 wt. % Si and has a structure essentially formed of ferrite in which a carbide of Ti and/or Nb is precipitated, martensite and retained austenite.