Process for manufacturing galvannealed steel sheet having excellent anti-powdering property
US5518769A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1994 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Oct 31, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C2/06
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
It is an object to provide a process for manufacturing galvannealed steel sheets exhibiting excellent anti-powdering property when press formed, and uniform frictional properties in a coil. A steel strip is galvanized in a bath having a low aluminum content after entering it at a high temperature as defined in relation to the aluminum content of the both, so that the formation of a .zeta. phase may be promoted. Then, the strip is heated for alloying in a high-frequency induction heating furnace so as to have a temperature not exceeding 495.degree. C. when leaving the furnace to yield a plated steel strip having a coating containing a uniformly distributed .zeta. phase. After such heat treatment and cooling, the strip can be plated with an iron or iron-alloy top coating having an iron content of at least 50% and a coating weight of at least 1 g/m.sup.2 to achieve an improved press formability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.