Method and apparatus for continuous treatment of a strip of hot dip galvanized steel
US5628842A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 21, 1995 |
| Grant date | May 13, 1997 |
| Priority date | — |
| Expiry date | Aug 21, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C2/29
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method and apparatus for continuously treating a strip of hot dip-galvanized steel. The method comprises the steps of rapidly reheating the strip to a predetermined temperature between 460.degree. C. and 600.degree. C., with a heating flux greater than 180 kWatts per meter squared based for each face of the strip; maintaining the strip at a substantially constant temperature for a predetermined period of time lasting between 10 and 30 seconds; and subsequently cooling the strip rapidly to a temperature below 420.degree. C., using a cooling flux of a magnitude greater than 100 kWatts per meter squared for each face of the strip. The step of rapidly reheating is performed following a drying operation conducted on the strip as it exits from a zinc bath. The apparatus comprises various elements for performing the method, as well as a vessel containing the zinc bath, redirecting rolls which define an upward and substantially vertical trajectory for the strip and a drying mechanism disposed along the trajectory downstream of the vessel's exit. Preferably, the rapidly heating of the strip is accomplished using an induction furnace operating at a frequency between 100 and 500 kHz, and th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.