Process for preparing surface-treated steel strips adapted for electric resistance welding
US4832800A · kind A · utility
Inventors
Key dates
| Filing date | Jun 8, 1987 |
| Grant date | May 23, 1989 |
| Priority date | — |
| Expiry date | Jun 8, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S205/917
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A surface-treated steel strip adapted for electric resistance welding is 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, wherein the electrolytic chromate treatment is carried out in a bath which contains an amount of a chromate compound to give 10 to 100 g/l of CrO.sub.3 and has a weight ratio of H.sub.2 SO.sub.4 /CrO.sub.3 in the range between 3/1000 and 1/100.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.