Heat treated galvannealed steel material and a method for its manufacture
US9045817B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 2010 |
| Grant date | Jun 2, 2015 |
| Priority date | — |
| Expiry date | Oct 19, 2032 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2221/00
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A heat treated galvannealed steel material having excellent post-painting corrosion resistance and a high strength which is suitable for use as an automotive part and a method for its manufacture are provided. A galvannealed steel material having a galvannealed coating on at least one side thereof is heat treated by heating at least a portion thereof to a temperature range in which hardening is possible. The coating remaining on the surface of at least a part of the portion which underwent heat treatment has a coating weight of at least 20 g/m2 and at most 80 g/m2 per side and an Fe content of at least 15% and at most 35%, an η phase is present in the coating, and the centerline average roughness Ra of the surface of the coating is at most 1.5 μm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.