Process for producing surface-treated steel sheet superior in weldability and paint-adhesion
US5248405A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1992 |
| Grant date | Sep 28, 1993 |
| Priority date | — |
| Expiry date | Jan 21, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12993
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A surface-treated steel sheet is provided, at a low cost, which has high weldability and is useful for a material of containers of foods and beverages. The surface treatment is conducted by applying flattened granular tin coating deposits having a specified diameter and high adhesion on a steel sheet surface at a specified plated area ratio, and applying thereon a metallic chromium coating and a chromium hydrate oxide coating. In the surface treatment, firstly, the surface of a steel sheet is subjected to tin-plating in an acidic tin plating bath containing a conventionally used brightener in an amount of from 0.001 to 0.05 g/1 so as to form flattened granular tin coating deposits having a diameter of 0.4-2.4 .mu. at a plated area ratio of 5 to 30% and to improve the adhesion to the steel sheet and decrease falling-off of the granular tin coating deposits until completion of chrome-plating, thereby the variation of the amount of tin coating being decreased. Subsequently, the sheet is plated with metallic chromium in an amount of 50-150 mg/m.sup.2, and further chromium hydrate oxide layer is formed in an amount of 2-40 mg/m.sup.2 as chromium. Thus a surface-treated steel sheet, whic…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.