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:
Apr. 27, 1999
Filed:
Jul. 16, 1997
Masahiko Hori, Nishinomiya, JP;
Toshio Nakamori, Ashiya, JP;
Yoshiaki Nakazawa, Kashima, JP;
Yasuyuki Tanno, Honjo, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A galvannealed steel sheet suited for use in automobiles, and a manufacturing method thereof. The steel sheet has tensile strength of 340 MPa or higher and paint bake hardenability of 10 MPa or higher, and excellent resistance to powdering when press formed, and excellent resistance to chipping in cold regions. The base metal of the galvannealed steel sheet consists essentially of C: 0.004-0.008%, Si: 2.5.times.P (%)-0.20%, Mn: 0.10-0.40%, P: 0.017-0.045%, sol. Al: 0.003-0.08%, Ti: 0.002-0.015%, Nb: 0.010-0.030 %, wherein Ti (%)+Nb (%): 0.012-0.035%. A steel sheet of the chemical composition described above is hot-dip galvanized, heated up to a Fe--Zn alloying temperature at a heating velocity of 20.degree. C./sec or higher, and upon completion of the Fe--Zn alloying process, cooled down from the Fe--Zn alloying temperature at a cooling velocity of 10.degree. C./sec or higher.