Surface-treated steel strips adapted for electric resistance welding
US4608320A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 1985 |
| Grant date | Aug 26, 1986 |
| Priority date | — |
| Expiry date | Jun 5, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12958
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Surface-treated steel strips suitable for electric resistance welding are prepared by forming a first layer of iron-nickel alloy on a steel strip, said first layer having a weight ratio of Ni/(Fe+Ni) in the range between 0.02 and 0.50 and a thickness of 10 to 5,000 angstroms, forming a second layer of tin or iron-tin-nickel alloy on said first layer by tin plating to a coating weight of 0.1 to 1 g/m.sup.2 of tin and optionally, causing the tin to reflow, and forming a third layer on said second layer by effecting an electrolytic chromate treatment, said third layer consisting essentially of metallic chromium and hydrated chromium oxide in a total amount of 5 to 20 mg/m.sup.2 calculated as elemental chromium. More preferably, the electrolytic chromate treatment is controlled such that at least 2 mg/m.sup.2 of metallic chromium is present in the third layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.