Surface-treated steel sheet for fuel tanks and method of fabricating same
US6387538B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 2000 |
| Grant date | May 14, 2002 |
| Priority date | — |
| Expiry date | May 8, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31942
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A surface-treated sheet for fuel tanks includes a cold-rolled steel sheet with a low carbon content, a zinc or zinc-based alloy plating layer formed on the steel sheet, and a chromate film coated on the zinc or zinc-based alloy plating layer. The chromate film is formed from a chromate solution. The chromate solution includes a subject solution and an aqueous silane solution in an amount ranging from 5 to 50% by weight of the subject solution. The subject solution contains a chrome aqueous solution where the concentration of chrome is in the range of 5-50 g/l and the ratio of trivalent chrome to the chrome content is in the range of 0.4 to 0.8. Phosphoric acid in an amount ranging from 20 to 150% by weight with respect to the chrome content, fluoric acid in an amount ranging from 10 to 100% by weight with respect to the chrome content, colloidal silica having pH of 2-5 in an amount ranging from 50 to 2000% by weight with respect to the chrome content, and sulfuric acid in an amount ranging from 5 to 30% by weight with respect to the chrome content are mixed with the chrome aqueous solution. The aqueous silane solution contains 2-10 wt % of Epoxy-based silane and has a pH of 2-3. A …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.