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. 15, 1983
Filed:
Jun. 13, 1979
Applicant:
Inventors:
Assignee:
Nippon Steel Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D / ; C21D / ;
U.S. Cl.
CPC ...
148 / ; 148 124 ; 148143 ;
Abstract
A method of producing a dual phase structure cold rolled steel sheet having tensile strength 35 to 50 kg/mm.sup.2, yield ratio less than 60% and high elongation which comprises hot rolling and cold rolling by conventional process a steel containing 0.01 to 0.05% C, less than 0.2% Si, 1.7 to 2.5% Mn, 0.01 to 0.10 Al with the balance being Fe and unavoidable impurities, holding the produced steel sheet for 20 seconds to 20 minutes at a temperature 720.degree. to 850.degree. C., and cooling the steel sheet at a cooling speed between 3.degree. and 50.degree. C. per second and also above a value (.degree.C. per second) shown by following formulae: