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:
Oct. 20, 1992
Filed:
Nov. 21, 1990
Hirohide Asano, Kimitsu, JP;
Kazuo Koyama, Kimitsu, JP;
Takaji Takahashi, Kimitsu, JP;
Nobuhiko Matsuzu, Kimitsu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
A building low yield ratio hot-dip galvanized cold rolled steel sheet having an improved refractory property, consists essentially of, by weight, 0.1% or less of C, 0.1 to 1.5% of Mn, 0.1% of less of P, 0.06% or less of Al, 0.6 to 2.0% of Cu, and a remainder of Fe and unavoidable impurities and having a 0.6 times or more yield point strength at 600.degree. C. compared to that at normal temperatures. The method of forming the steel sheet comprises the steps of: forming a slab from a steel consisting essentially of, by weight, 0.1% or less of C, 0.1 to 1.5% of Mn, 0.1% or less of P, 0.06% or less of Al, 0.6 to 2.0% of Cu, and a remainder of Fe and unavoidable impurities, immediately or after heating the slab at a temperature of 1200.degree. C. or less, hot rolling the slab at a temperature of 750.degree. C. or more and cold rolling, effecting a continuous hot-dip galvanizing process, heating the rolled slab at a temperature of 700.degree. to 900.degree. C. in a reducing atmosphere, cooling the rolled slab at an average cooling rate of 3.degree. C./sec or more and dipping the rolled slab in a hot-dip galvanizing bath.