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. 31, 1994
Filed:
Feb. 22, 1993
Masaru Sagiyama, Tokyo, JP;
Masaki Abe, Tokyo, JP;
Akira Hiraya, Tokyo, JP;
Junichi Inagaki, Tokyo, JP;
Masaya Morita, Tokyo, JP;
NKK Corporation, Tokyo, JP;
Abstract
A method for manufacturing an iron-zinc alloy plated steel sheet having two plating layers and excellent in electropaintability and press-formability, which comprises the steps of: applying an alloying treatment under a temperature of from 420.degree. to 520.degree. C. to a zinc dip-plated steel sheet to form on the surface of the steel sheet an alloying-treated iron-zinc alloy dip-plating layer having on the surface thereof fine irregularities comprising numerous fine concavities and numerous fine convexities; then applying a temper rolling treatment at a reduction rate of from 0.3 to 1.5 to the alloying-treated steel sheet, to level the numerous fine convexities on the surface of the alloying-treated iron-zinc alloy dip-plating layer, so as to form on the surface of the steel sheet the alloying-treated iron-zinc alloy dip-plating layer as a lower layer having the numerous fine concavities on the surface thereof; and then applying an iron-zinc alloy electroplating treatment to the temper rolling treated steel sheet to form, on the alloying-treated iron-zinc alloy dip-plating layer as the lower layer, an iron-zinc alloy electroplating layer as an upper layer. The above-mentioned iron-zinc alloy electroplating treatment is carried out with an electric current density of from 50 to 150 A/dm.sup. 2 in an acidic electroplating bath containing iron ions and zinc ions, and having a pH value of from 1.0 to 4.0 and a temperature of from 40.degree. to 70.degree. C.