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.

Date of Patent:
Jan. 19, 1993

Filed:

Jan. 16, 1992
Applicant:
Inventors:

Susumu Masui, Chiba, JP;

Kei Sakata, Chiba, JP;

Fusao Togashi, Chiba, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C23C / ; C23C / ;
U.S. Cl.
CPC ...
148533 ; 148331 ; 148333 ; 428659 ;
Abstract

A galvanized steel sheet is provided which has a tensile strength of not less than 80 kgf/mm.sup.2 and a yield ratio of not more than 60%, and which is applicable to members of an automobile body, particularly those requiring strength. By appropriately controlling the amounts of components, such as C, Mn, Nb, Ti and B, the structure of the steel sheet is formed into a dual-phase structure having a second phase strucutre. The steel sheet is recrystallization-annealed, galvanized while it is maintained at a temperature range near 500.degree. C., and then is cooled. By controlling the rate of cooling the steel sheet, the second phase structure generated is prevented from hardening more than necessary. A galvanized high-strength steel sheet is obtained which has a low yield ratio and excellent stretch-flanging properties.


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