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. 24, 1989
Filed:
Feb. 10, 1989
NKK Corporation, Tokyo, JP;
Abstract
A method for manufacturing an electrolytically chromated steel sheet, comprising the steps of: subjecting a steel sheet to an anodic electrolytic treatment with a quantity of electricity of from 0.3 to 30 coulomb/dm.sup.2 in an acidic electrolyte containing at least one of chromic anhydride, chromate and bichromate, to form a hydrated chromium oxide film having numerous holes and numerous thin portions over the entire area of at least one surface of the steel sheet; and then subjecting the anodically treated steel sheet to a cathodic electrolytic chromate treatment in an acidic electrolytic chromating solution to form on the at least one surface of the steel sheet a chromate film comprising a metallic chromium layer as a lower layer having thereon numerous granular projections, and a hydrated chromium oxide layer as an upper layer. The electrolytically chromated steel sheet manufactured in accordance with the method of the present invention has excellent secondary paint adhesion and weldability, and has a satisfactory surface hue.