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. 20, 2003
Filed:
Jul. 20, 2001
Jae-Ryung Lee, Pohang-shi, KR;
Sam-Kyu Chang, Pohang-shi, KR;
Sang-Geol Noh, Pohang-shi, KR;
Soo-Hyoun Cho, Pohang-shi, KR;
Pohang Iron & Steel Co., Ltd., Kyungsangbuck-do, KR;
Abstract
The present invention relates to a surface-treated steel sheet coated with a chromate layer having excellent corrosion resistance, fuel resistance and seam weldability, and a chromate solution used for preparing the surface-treated steel sheet. Specifically, the chromate solution of the present invention comprises (a) a main solution prepared by adding to a chrome solution having 0.4 to 0.8 of trivalent chrome composition and 7 to 50 g/l of dissolved chrome, on the basis of the chrome in the chrome solution, 50 to 80 w % of phosphate, 20 to 40 w % of fluoric acid, 300 to 2000 w % of colloidal silica, 5 to 15 w % of sulfuric acid, and 25 to 40 w % of sodium phosphate, and (b) a hardener solution containing added epoxy silane or glycidyl silane of 2 to 10 w % on the basis of total hardener solution, the pH of which is controlled between 2 and 3, wherein 10 to 60 w % of the hardener solution being added to the main solution.