Process for preparing surface-treated steel strips adapted for electric resistance welding and strips produced by said process
US4561943A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1984 |
| Grant date | Dec 31, 1985 |
| Priority date | — |
| Expiry date | Jul 6, 2004 |
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, this 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 the 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. A third layer is formed on the second layer by effecting an electrolytic chromate treatment, this 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. Preferably, the electrolytic chromate treatment is controlled so 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.